Question: how to legally change your child's last name in missouri?
Answer: Step 1 – Fill-in Petition for Change of Name by Parent (or Next Friend) ... 
Step 2 – Notarize Petition for Change of Name. ... 
Step 3 – Obtain Notarized Consent (If Applicable) ... 
Step 4 – Gather Documents. ... 
Step 5 – File Petition with Circuit Court. ... 
Step 6 – Pay Filing Fee. ... 
Step 7 – Attend Possible Hearing.