IRS says:
If the Filing Status differs from the Filing Status on the Original Return, then the Amended Return must be filed by paper.
If your kids e-Filed, they (or you) can change the dependent status and e-File 1040-X.
In Part III explanation,
just put that you are amending to change dependent status.
If your kids filed to collect EIP1 and/or EIP2 (Form 1040 line 30), they will have to give that up.
