Thnx to @drsk’s another great scenario we have a new interactive tutorial on one of the basic and most used DAML patterns, i.e., the propose/accept pattern. As he puts it himself
The Propose/Accept pattern is the only way you can create contracts with multiple signatories. It is also an elegant way to delegate rights to a party by creating a role contract for it. In that way, the Propose/Accept pattern complements the Role pattern.