RHO: 1C --> LHO: 1S --> RHO: 2D
Does this mean 4-4 in clubs/diamonds, or 5-4 in clubs diamonds. Is it a reverse? (e.g.18+ pts?).
Assuming opponents play SAYC.
The point to a "waiting reverse" is when opener has multiple options for a non-ideal bid, and wishes to set the denomination after responder rebids. It should be done only in a suit below 2 of responder's suit, unless opener is stronger than a minimum reverse. As noted it is often done with 3 of responder's suit to see if responder can rebid it. It often implies slam interest, as the extra information communicated may be of more use to the defence in merely a game contract.
With a minimum reverse, opener must be able to retreat to either 3 of responder's suit or 3NT if the reverse suit is raised.