POST api/RoundTripAssignment?roundTripAssignment_Id={roundTripAssignment_Id}&roundTripHasStarted={roundTripHasStarted}&roundTripHasEnded={roundTripHasEnded}&roundTripHasCancelled={roundTripHasCancelled}&roundTripUserComments={roundTripUserComments}&roundTripUserRating={roundTripUserRating}