Autolayout RTL support in app

I am aware that iOS has the RTL (right to left) support for languages, and that by using leading and trailing constraints I "tell" autolayout to stack the elements according to the language orientation. This all works great. If I want a constraint to be fixed, I turn off respect language direction and there is no problem. However I need to make in app language selection, which will have LTR and RTL languages. How to signal the app to mirror the view to RTL and vice versa? I know this could be done if I would iterate through constraints and change the leading/trailing to left right and vice versa, but is there any simpler solution for that? App restart is also fine if needed! Solution should support iOS 8.x + Thank you