Here is a post from
TurboTaxWill about amending returns:
You should not try to amend your return until the original return
it has been fully processed and you have received your refund or your payment
has cleared.
Amended returns do not “catch up” to your original return and replace them;
they are processed as two separate returns.
Amended returns have to be printed and filed by mail. It can take
the IRS up to 12 weeks or longer to process them. If you are
due a larger refund than on your original return, your amended return should
only show the difference and you will receive a separate check for
it. If you owe money on your amended return, it will show only the
new amount owed, you will have to mail a check with the return.
Click here for amending instructions:
https://ttlc.intuit.com/replies/3288565