I just amended two just like you yesterday. You have to do an amendment. Spell it out very clearly in Section III exactly what happened. There is no other place on the form to fix it.
I'm not sure about that. I think that if you do nothing, you will forfeit the money, period. The IRS is not going to check your claimability against what you stated on your return. If you amend and they accept it, you will get your money either later this year or some time next year. That is my understanding of what the IRS is currently saying.
