As with a half court trap (42), X1 overplays the ball handler towards a sideline. When the dribbler is 3 strides away, X2 runs under control and with hands up towards her outside shoulder. When X2 reaches the dribbler, X1 does not trap with X2, but rather runs through to pick up X2's check. X1 and X2 switch checks.
A run and jump defense can be called from the bench, or it can be an option out of 42 instead of trapping. Here X2 would yell "Jump" to signal that X1 should jump switch.
Here are the positions after a jump switch. If ball handler O1 is expecting a trap, she may try to make a pass to O2 that can be intercepted by X1. O1 could also charge, travel, or pick up her dribble.
This jump switch involves only two players, and, because there is no trap, there is no rotation by other players.