Retirement tax questions

I filed the amendment back in March 2025. This week I received a letter from IRS acknowledging that they received my amended return and asking me to complete the form 1040-x to support the changes made with the amended return. They also suggested to provide form 1099-SA with the changes to complete the processing the amended return.

I am confused because I thought the amended return would send the 1040-X with all the information. When I downloaded the amended return, I could see 1040-X.

So are they wanting me to download a new form 1040-X, complete the form and send it or should I be sending the completed form that I downloaded while filing the amended return? 

I tried calling them and was on phone for 1.5 hours waiting to connect. Appreciate any suggestions.

Thank you.