In 2015, I did not add the distribution to line 14a of form 8889 and did not enter that all of the distribution was used for qualified medical expenses on line 15. How do I amend the 8889 form to resubmit to IRS? Must I also resubmit entire 1040 if Line 21 Other Income remains as 0?
A 1099-SA distribution only shows up on the form 8889, it doesn't get reported on line 14a. After you amend you must mail in the 1040X plus the form 8889 even if the bottom line doesn't change.
tmazoo was referring to line 14a of Form 8889 where the box 1 amount from the Form 1099-SA is required to be reported. Assuming no rollovers or returns of excess contributions, that amount will also appear on line 14c. The amount used for qualified medical expenses goes on line 15 and the difference, zero if all was used for qualified medical expenses, goes on line 16.