Sorry an amended return won't clear her ssn from the IRS. She will have to mail her return. But you don't have a choice who can claim her. Even if you don't claim her then on her return she still has to say she CAN be claimed. What do you mean you are waiting for the IRS to tell you about the amending? You have to file the amended return which won't be ready until later this month.
It would be unusual for a 18 year old to not be your dependent. You can claim her if she is under 19 or under 24 and a full time student no matter how much she makes.
Who can you claim
https://ttlc.intuit.com/community/credits-and-deductions/help/who-can-i-claim-as-my-dependent/01/267...
Do you have to answer YES if you are a dependent but not being claimed
https://ttlc.intuit.com/community/dependents/help/when-do-i-have-to-answer-yes-to-being-claimed-as-a...
