While the vehicle is moving forwards, the driver can pull a lever that makes it stop and go backwards at the same speed.
During, the pressure rise,F-R clutch is in energized condition which makes the vehicle to move forward/Reverse direction.
In this case generally forward reverse synchronizers are replaced by the multi-plate friction clutches.
This is beneficial to the forward reverse control elements as they are not subjected to the high relative torque.
The challenge involved in providing this feature in the existing transmissions is the complex shaft arrangement.