I found this video really great:
In there he says that roughly, not everything will map and don't force it. But before he says that he gives two examples where he needed to rethink his objects and CRUD.
For example, with your assign. What are you assigning? Are you, instead, actually creating a relationship between two objects. If so, then use CRUD (and REST) to create and manage the relationship.
Also, it sounds like Transfer, Escalate, and Redirect are actually just special cases of update.
But, the main thing I took away from that video is a philosophy of not forcing anything.