change back
(from something) to return to the original form, state, or selection, from some other form, state, or selection. We are going to change back from our position of last month. We didn't like our new plumber, so we changed back.
change back
((in)to someone or something) to return to the original form. The crisis in Congress changed back to a minor matter within a week. Then Superman changed back into mild-mannered Clark Kent.
change something back
to cause something to return to the original or a previous form. Whoever changed the television channel should change it back. Change back the channel to the game!