After you file

That makes no sense.   If you deleted a dependent correctly before you filed, the dependent would not be shown on your tax return at all.   Sorry----you are just going to have to wait for the IRS and see if the e-file is accepted or rejected.   If it is rejected, you can delete the dependent in MY INFO.    If the IRS accepts your e-file with your sister shown as your dependent, refer back to the information given to you earlier.   Sister will have to file by mail, and you will have to amend.

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