Thank you! Sorry...yes more details. This is a new client for me and the prior year preparer left out a composite 1099 which had a loss of over 3K. I found it on the client's transcript which I had permission to view. Client currently owes around 9k and has made a payment plan with IRS. I would like to run the numbers to amend and see what the capital loss brings the liability down to. I think an amendment is necessary either way. I researched it a bit more and I believe that I need to file the amended return 1040 X, then file the 843 once it is processed. Have I done in something out of order in asking the client to make a payment plan first?