The policy of the majors is:
An II exchange can only be gifted---no compensation whatsoever. Cancelling an initial exchange gives you a replacement week (with potentially degraded trade power) usable for one year from the date of cancellation. If you cancel within 59 days, you can only book within 59 days with the replacement week. If you cancel again, you lose the week.
An RCI exchange may be rented, but only for the cost of the exchange fee plus guest certificate. If cancelled, you get the original week back (likely with significantly degraded exchange power, as if you'd deposited it late) with its original travel window.
I've had two cancellations so far. One was an RCI week in Orlando where a later DVC exchange came through in II. The other was a week I booked for my brother as a gift, but his work schedule changed last minute. In both cases, I just cancelled and used the weeks for something else. But, they were also Wyndham generic points weeks, and those revert to their original trade power (because all generic weeks at a given point level have the same--lousy--trade power.)
