@Keildo wrote:
(1) Should I send my entire tax return to the IRS in this fax or just those pages that have changed?
Just send the pages that have changed. That will probably be just Form 1040 and Schedule 3 (each of which is 2 pages). If there are no other entries on Schedule 3 - in other words, the corrected Schedule 3 is blank - you could omit Schedule 3 and just send the corrected Form 1040. On the corrected Form 1040, lines 20 and 31 will be blank.
@Keildo wrote:
(2) Should I still file an amended return (i.e. using form 1040-x) at some future date?
You should not file an amended return unless the IRS specifically asks for it. What I expect will happen is that the IRS will adjust your tax return based on your reply to the letter, without any need for an amended return.
