I am confused as to which form to use for this scenario. In FY 2007, corporation filed Form 1120 and paid $1286 in fed income tax (based on $8576 in taxable income). Subsequently, in 2008, received IRS approval for 501c3 status with effective date back in June 2006. So, I want to file to get the $1286 in income tax paid for FY 2007 back b/c now considered tax-exempt for FY 2007 based on effective date of 501c3 approval. I've looked at Form 1120x (Amended US Corp Income Tax Return), but can't figure out how to fill in the numbers to make it work - I simply want to state that we overpaid by $1286. Since we also should not have filed a 1120 in the first place as a 501c3 org, it seems like 1120x doesn't anticipate this scenario. An local IRS employee told us to use Form 843 (Claim for Refund), but in the instructions, 843 states to NOT use 843 to request a refund of income tax, which is essentially what I'm trying to do. We are made up of volunteers, so really want to avoid hiring an outside accountant for what should be a fairly straightforward request to IRS. Please help.