It's look like you want to amend your 2015 tax
return? In my case, I am changing my filing status from filing separately to
filing jointly. I have some changes for example; the total gross income and
exemptions amounts will be increase. You
may have to include or exclude some credits depending upon the status. For
example, my educational credit wasn’t included in filing separately but you can
in filing jointly. In short, you don’t
change the whole return. Form 1040X is the form that you need to use to amend
your tax return. It will show the
increase and decrease of amount to be changed in that form. I hope this will
help you. Good luck.