Turn off the electricity powering the exhaust fan from the main circuit breaker. Use an electrical circuit tester to test the wires to ensure no electricity is running through them.
Remove the grille in the bathroom to expose the electrical wiring inside the box. Unscrew the wire nuts holding the wires together. Separate all of the wires.
Cut the foil duct tape around the elbow of the vent fan with a utility knife. Remove the tape and take the flexible duct off of the housing.
Remove the screws holding the housing to the trusses with a screw gun. There should be four screws, one in each bar coming off each corner.
Lift the old bathroom exhaust fan up and out of the trusses.