We have a mix up with the TP and Spouse's ITIN's and one return has already been accepted. What to do?

jeanmarc · ‎06-02-2023

TP and spouse are Married Filing Separately. They came into do their taxes at separate times. Both have ITIN's.
The wife did her tax first but accidentally gave us her husband's ITIN. We e-filed and the IRS accepted the tax with the wrong ITIN and she even received her refund.
Husband came in later to prepare his tax return and that is when we realize that his wife had accidentally given us his ITIN instead of her own.
I don't know why the first return was accepted with the wife's name and his ITIN, unless ITIN's are not checked by the IRS with the same precision as SSN's.
What would you say is the best course of action? An amended return? For the husband and wife to go to the IRS with both their returns and ITIN's and explain the mixup? I'm open to suggestions.