To create an amendment when another agent lodged the original:
Input the original tax return.
Check that the return has no validation errors.
Close out of the return and mark the status as Lodged.
Add a new Tax form to attach the correct sequence number to the amended return. See How do I amend a tax return? if unsure of the process.
Note: If you are unable to open the Amended Tax form Seq1, delete the form and create a new Amended Tax form Seq1.