If my tax return gets rejected and I got back and I am able to go back and make changes, will I also still have to fill out a 1040x. Or can I just make changes and resubmit it again without also have

You do not fill out a 1040X form, you never amend a return if the original has not been accepted & fully processed.

If your return gets rejected, you can just make the changes you need to do, then you can e-file your return again.  

If your return gets accepted, then once your original return is fully processed, you would have to amend your return to make changes.