Add "Back" step in "Flow Builder"

Feature Request Summary: 

I would like to add a "Go back" step to "Flow Builder".

Description/Use Cases: 

Currently the "Flow Builder" does not allow to "go back to the beginning" until the end of the flow.
If a customer is in the middle of a "messaging" guide and the information is not what they want, they want to go back to the beginning of the flow immediately.

Business impact of limitation or missing feature:

If customers can't find the information they want in messaging, they will feel stressed and leave.
Or it leads to a never-ending volume of inquiry tickets.

Thanks.