My daughter filed w/o checking "Someone can claim you as a dependent". My return was rejected. We amended her return, it hasn't processed. Should I request an extension?

The amendment was required , but waiting won't help.

Because of the way the IRS works, you must file a paper tax return via US Mail.

@kwinings 

No you don’t have to wait to file your return since you have to print and mail yours.   Once a ssn has been used you can’t efile it again even if they amend.