Backtrack workflow in REST
Simple answer is No - It's not possible.
Unless of course you add a feedback loop to your process.
So for example you could design your screens as follows (5 only):
Screen 1 - input fields -> Next button
Screen 2 - input fields -> Next button + Back Button (to Step 1)
Screen 3 - input fields -> Next button + Back Button (to Step 2)
Screen 4 - input fields -> Next button + Back Button (to Step 3)
Screen 5 - input fields -> Submit button + Back Button (to Step 4)
There is no way to do this in REST - that's not it's function. You have to do it in the process design.
You should also note that if you go back from Step 4 to Step 1 then you HAVE TO also negotiate going through all other Steps (2 and 3) as the change in 1 may affect how 2 or 3 operate. So be careful.
You will have to design your process like this though if you want it to work,
PS: If this reply answers your question, please mark as resolved.