So at this point if you have made any changes to your already e-filed and accepted 2017 tax return, you need to change it back to match *exactly* what you originally e-filed with the IRS. If you do not do this, then when you do amend you will have major issues with the IRS.
You cannot amend 2017 yet. You cannot change or add anything on the return that you just e-filed, nor can you stop it. It is too late, just like when you put an envelope in a US mailbox
Now you have to wait until the IRS either rejects or accepts your return. If your return is rejected, you will be able to go into your account and make the necessary changes to your tax return and re-submit your return.
If the IRS accepts your return, however, then you have to wait longer until it has been fully processed and you have received your refund. THEN you can prepare an amended tax return and mail it in. You will need to use a form called a 1040X. You cannot e-file an amended return. They have to be mailed, and it takes about 4 months for the IRS to process. Meanwhile, DO NOT go in and start changing anything on your return in the system, or you will make a mess for yourself. Sit tight and wait until you see what the IRS does with the return you just e-filed