If you are using the Desktop program installed on your computer you can make as many tax returns as you want. You can start another new return, go up to FILE-NEW. You can copy your first return to test tin, Go to FILE - SAVE AS or Duplicate and give it another name. There is a What-If worksheet you can use.
Go to Forms Mode, click Forms in the upper right or on the left for Mac. Then click Open Forms box in the top of the column on the left. Open the US listing of forms and towards the bottom find the What-if worksheet. It's right under Estimated Taxes.
Or try…Go into Forms View. Once there, at the top of the left column, click on the icon for "Open Form". A popup window will appear. In the text line, type the word "what" without quotes. You should see "what-if worksheet" appear as a selection choice. Double-click it to launch the form.
Why are you switching? Do you just want to test? Or do you need to file Joint for Federal but Separate for states?
