"Pause at Z height" is right under my "Pause" button on the Flashforge menu. I just entered the MM height of 4.02 and it auto paused there.

It is just like any manual pause, the bed lowers down, the extruder returns to it's home position (it's not freely movable from there though) and I just pull the filament out and load in the new filament, and "Unpause" bring's the bed back up and nozzle to right where it left off.