Get support. Talk to another person... to get support

Make it three people in the conversation:


(1) A & C are talking. A tries to convince C. A turns and talks to B in the room to bring B into agreeing with A, in front of C.
 
(2) A talks to C. No one else is in the room. A wants support. So, what to do? A brings B into the conversation by quoting B that agrees with A