I submitted my tax return but it was rejecreed

Yes,  if she does not qualify as your dependent, you must delete her from your tax return.  Since your return was rejected you can make any and all corrections prior to resubmitting.

You would delete her from the dependents section in the "Personal Info" area.

Below is a reminder of the criteria for claiming someone as a dependent child.

1. The child must be your son, daughter, stepchild, foster child, brother, sister, half brother, half sister, stepbrother, stepsister, or a descendant of any of them.

2. The child must be (a) under age 19 at the end of the year and younger than you (or your spouse if filing jointly), (b) under age 24 at the end of the year, a student, and younger than you (or your spouse if filing jointly), or (c) any age if permanently and totally disabled.

3. The child must have lived with you for more than half of the year.

4. The child must not have provided more than half of his or her own support for the year.

5. The child must not be filing a joint return for the year (unless that joint return is filed only to claim a refund of withheld income tax or estimated tax paid).