Hello,
- Are you trying to change your child's D.O.B. in his Microsoft Account profile?
- Is your child already a part of the family group?
https://account.microsoft.com/family/home
Only the Family Organizer has permission to edit the date of birth on a child's account. To do this, the child account must first be part of a Microsoft family group.
If the Child account is not a part of the Family Safety group:
- Open an incognito tab.
- Sign in with your Microsoft account (an Adult Account, not a child's) using the link below. https://account.microsoft.com/family/home
- Invite the Child account to the Family group.
- Accept the invite from the child group.
- Once accepted, you will see your child's account profile in the Family safety settings.
- Select Manage consent > Edit child's profile info.
- Change the D.O.B. to Adult.
If your child is already part of the Family Safety group, you should be able to change his D.O.B. directly on his account.
Let me know if you still need more help.