Do not send an amended return with the W-7. The IRS are not processing paper returns. And with the W-7 you need to send the passport and some other required documents. I asked 2 of my clients to go to the local IRS and submit the form W-7 with the 1040 so they can show the documents last March, 2020 rather than mailing.  The local IRS marked the W-7 and 1040 as received. I attached a copy of the marked W-7 and 1040 to the state return, South Carolina. But until now neither of the 2 received a letter from the IRS. I would assume the W-7 and the 1040 were not sent to the processing center for the W-7. Our local IRS office closed the last week of March, 2020.  But  they received received a letter from the state asking for the ITIN or SS number because IRS did not processed the W-7. 

Also my client sent a check to IRS in March  with the form 9465 until now it did not clear in the bank and the installment plan scheduled monthly every 15th starting in April were not also drafted in the bank. My client did not received a confirmation letter on the form 9465. I would assume the paper returns are sleeping in the processing centers. I know the excuse is Covid. But why my state, South Carolina are doing their job not the Internal Revenue Service.