An amended return doesn't stop the original return or over write it ... it is processed as a second return only after the original return has processed.
You MUST wait until both returns are processed and the original returns have been received BEFORE you can amend either return. The amendment function will not even be operational until after 2/15 sometime so you can't even do so until then. So take a deep breath as this is going to take some time and effort and must be done in order according to the processing rules.
