If you filed, it is like dropping it into a mailbox - you cannot get it back.
The IRS just started to accept returns yesterday. If you receive an email that your return has been accepted then you will have to wait until the return is processed. If for some reason your return has been rejected, that means you will have an opportunity to correct the rejection and add the form 1095-A prior to resubmitting.
If accepted, it's likely the IRS may catch the error and ask you to submit form 1095-A. If the IRS asks for the form, you will simply follow their instructions and this will avoid any need to amend.