@Dave L2
since you initially filed for the Rebate Credit having this amount on line 15 Col A and Col C is strictly correct.
It is your exemption status that denied it.
The only way to change your exemption status is to put in Part III Explanation that you are amending to set "no one can claim me".
The tricky part is your refund payment was adjusted downward by IRS (1040-X line 18)
you have to enter that adjusted value on line 18 so that you get a refund on line 22 equal to your EIP1 + EIP2.
TurboTax makes this part difficult.
For that reason you might have to file on paper.
NOTE: if you are not changing any amounts originally filed, you don't have to fill out Columns A,B,C
You can leave that all blank.
You can get the 1040-X in fillable PDF format on IRS website.
In this case (unless I'm missing something) there are no related Forms or Schedules changing that you would have to attach.
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After all that, expect to wait six months or more for IRS to approve your emended tax return.
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Of course, this all assumes you were not listed as a dependent on any other person's tax return.
