2020 Instructions for Amended Tax Returns Failing Fed and CA Return

"Yes in my post I followed that link. It says to save the file but name it something else. So now that I created a new file for amendment I assume to fix the issue of duplicated SSN I can just remove the e-file option on the original. Is that correct?"

That part in red is wrong.

You want to save a copy of the original (and uncheck the EF boxes on it for both fed and state), but use the actual original file as the amended.  You cannot use the copy for the amended return.

Skip this first section if you dont want backstory

Ive been having this issue for 2 weeks. I recreated a 2020 return, efiled by another preparer. i saved it. I made the changes for 1040X/500X and "Saved As" a new file. I clicked the 'efile federal return', clicked 'efile federal amended return', and clicked 'marked original return as efiled'. but i forgot that the IRS doesnt accept 9465's for previous years for the current efile system. I sent it, they received it, and I got a rejection code, of course for the ridiculous 9465 issue. When I tried to efile the amended return, 4 rows showed up, and the box next to "federal amended return" was greyed out; it said in the status area, "not ready", and in the reason area, "federal return not completed". It drove me nuts. So i backed up the original and the amended file, to try a few things. 

Solution:

Once you receive a 'Rejected' status from the IRS, go back to the amended file, and UNCHECK the FIRST "efile federal return", just under Part VI, ABOVE the box of states that can be efiled. Do the final reviews, click "File Electronically" on the left sidebar as if you were normally efiling. 3 rows will show up, and The box next to "Federal amended return" will now be open. Click it, and efile it. Because you still have the error of unchecking the "efile federal return", it won't actually efile. It's an automatic failure bc of not passing the review portion. Once you get that failure status, open the same amended return, RECLICK "efile federal return", and go through the reviews, and efile like normal. THIS time, all 4 rows will appear, and the box next to "federal amended return" will be open. Click to choose it, and efile as normal. You should receive an efile successful status, and in my case, i got an "Accepted" status after about 10 mins. Until Proseries fixes this, I think this might be the only fix. 

and fyi, you can use a separate amended file to efile. I always done it that way. Create original, save, make changes, save as, and efile. 

https://proconnect.intuit.com/community/proseries-tax-discussions/discussion/2020-instructions-for-amended-tax-returns-failing-fed-and-ca/00/170981