iOS design pattern for multi-mode app

I will explain my question by way of example.

1. I'm writing a iOS app, that have 4 type of users. For every type of users i need to show different controller, and sometimes the same controller but with some changes.
2. It is possible to change role of user runtime. For switching between users i think to use Decorator pattern.

So what is the best solution to create (1) and (2) situations?