Detailed Answer

Short answer: To prove you are the decedent’s next of kin and to be appointed administrator of a reopened estate in Missouri you will typically need a certified death certificate plus primary documents that prove your relationship to the decedent (birth certificates, marriage certificate, adoption decree, divorce decree, court orders establishing paternity, etc.), plus the standard probate filing materials (a petition for letters of administration, an oath, bond or waiver of bond, and an affidavit or notice evidencing who the heirs are). You must also show a valid reason to reopen the estate (newly discovered assets, unresolved creditor claims, clerical errors, or other grounds).

How this works in Missouri

Missouri law follows statutory rules for who has priority to be appointed administrator and how intestate property passes to heirs. The court will examine evidence of family relationships to identify heirs under Missouri’s descent-and-distribution rules and to determine which person (if anyone) has priority to serve as administrator. For the statutory rules on appointment of administrators and intestate succession, see the Missouri Revised Statutes chapters on Executors & Administrators and Descent & Distribution:

• RSMo Chapter 473 — Executors and Administrators
• RSMo Chapter 474 — Descent and Distribution (intestate succession)

Typical documentation the court will expect

Organize certified, original or certified-copies where possible. The probate court relies on formal evidence:

• Certified death certificate: A certified copy from the issuing vital records office. The court will not proceed without this.
• Proof of relationship (primary evidence): Birth certificate showing the decedent and you (for child/parent relationships); marriage certificate (to prove surviving spouse status); adoption decree (for adopted children); certified divorce decree (to show former spouse status); court order of paternity or legitimation.
• If direct documentary proof is lacking: Court-certified records (e.g., guardianship records), baptism/family Bible entries, school records, medical records, contemporaneous correspondence, or sworn affidavits by people with direct knowledge can be used to support kinship — but the court prefers primary documents.
• Affidavit of heirship / family chart: A sworn affidavit or genealogical chart listing potential heirs, their relationships, and contact information. This helps the court identify and notify heirs. Missouri courts commonly require formal notice to identified heirs.
• Probate filings to request appointment: A petition for appointment of administrator or a petition to reopen the estate (depending on the county form and local practice); proposed Letters of Administration form; an oath; and local filing fee.
• Bond or waiver of bond: Missouri often requires an administrator to post a bond unless all interested parties waive bond. Be prepared to file a bond or secure written waivers by the heirs (see RSMo Chapter 473).
• Proof of prior probate or closing order (if estate was previously closed): If you are asking to reopen a closed estate, attach certified copies of the original probate case file, the decree or order that closed the estate, and a written explanation and evidence showing why reopening is necessary (for example, newly discovered assets, unadministered property, or unresolved claims).
• Renunciations or consents from persons with priority: If someone with higher statutory priority is willing to renounce their right to appointment, a signed renunciation or consent filed with the court will allow the next person to be appointed.
• Identification and contact information: Government ID for the petitioner, and contact information for all known heirs and interested parties to satisfy service/notice requirements.

Grounds and steps to reopen a closed estate

Common reasons to reopen include discovery of unadministered assets, a valid unpaid creditor claim discovered after closing, clerical errors, fraud, or misidentified heirs. The typical steps are:

1. Gather proof of the new fact (bank statements, title, creditor invoice, or other documentary proof).
2. Obtain certified copies of the original probate file and closing order.
3. Prepare and file a petition (often called a petition to reopen or for revivor and appointment) explaining the facts and asking the court to reopen and, if needed, appoint an administrator.
4. Provide the kinship and identity documents listed above, and demonstrate why appointment of an administrator is necessary.
5. Serve notice to heirs and interested parties according to Missouri rules and local court procedures.
6. If the court finds good cause, it will reopen the estate and either reinstate the former personal representative or appoint a new administrator according to statutory priority and evidence provided.

Priority to be appointed administrator

Missouri statutes set a priority list for appointment (for example, typically the surviving spouse, adult children, parents, siblings, or other next of kin). If a higher-priority person is unwilling or disqualified, the court may appoint the next in line. Written renunciations from higher-priority persons speed the process. See RSMo Chapter 473 for appointment rules and bond requirements: RSMo Chapter 473.

If relationship is disputed or documentation is weak

The court may order further proof: DNA testing (in rare cases), subpoenas for records, testimony from witnesses, or formal hearings. If multiple persons claim priority, the county probate court will hold a hearing to determine the proper appointment.

Practical checklist to prepare before you file

• Obtain multiple certified copies of the death certificate.
• Collect certified vital records proving your relationship and those of competing heirs (birth, marriage, adoption decrees, divorce). If records are unavailable, collect contemporaneous documentary evidence and sworn affidavits.
• Obtain the original probate file and final decree from the county where the estate was first administered.
• Prepare a clear affidavit or family-tree document showing heirs and their addresses.
• Get written renunciations if higher-priority people won’t serve.
• Be ready to post bond or collect written waivers of bond from the heirs.
• Draft a short cover petition explaining why the estate should be reopened and why you should be appointed administrator.

For the specific filing forms and county procedures, contact the probate court clerk in the county where the original estate was handled or where the decedent lived. Local courts often have specific forms and fee schedules.

Where to read the statutes

Read the Missouri statutes that govern appointment of administrators and intestate succession here:

• RSMo Chapter 473 — Executors and Administrators
• RSMo Chapter 474 — Descent and Distribution (intestate succession)

If you reference any statutory text directly, use the official Revisor pages for precise language and current amendments.

When to consult a lawyer

If heirs dispute kinship, if the estate has substantial assets, if fraud is alleged, or if reopening will trigger complex creditor or tax issues, consult a probate attorney. A lawyer can (1) review what documents you need, (2) prepare the petition and bond paperwork, (3) represent you at hearings, and (4) help negotiate renunciations or waivers.

Disclaimer: This article explains general Missouri probate concepts and common documents used to prove next-of-kin status and seek appointment as an administrator. It is informational only and is not legal advice. For advice about your specific situation, contact a licensed Missouri attorney.

Helpful Hints

• Start with the certified death certificate—courts almost always require it.
• Certified vital records (birth, marriage, adoption) are the strongest proof of kinship—order them early because they can take time to arrive.
• Get certified copies of the original probate closing order and file—those documents are essential when asking the court to reopen the case.
• If a higher-priority heir is available but won’t serve, ask them to sign a written renunciation to speed appointment.
• Prepare a clear heirship affidavit and provide good contact information for all heirs—courts need to give notice to interested parties.
• Check local county probate clerk procedures and forms before filing—procedures vary by county.
• Keep originals and certified copies organized and bring them to any hearing; the court prefers certified records.
• If you expect opposition, contact a probate attorney early to reduce procedural delays and to present evidence effectively.