Follow the "Retrofit Instructions from AK-450 to AK-451" provided by Ameri-King:

1. Swap the followings items: ELT with mounting tray; Antenna with Coaxial Cable; Remote Switch Unit with Buzzer.

Note 1: All mounting holes and cut out holes are exactly the same.
Note 2: Wiring Harness, between ELT and Remote Switch Unit, is exactly the same i.e. Do not change the wiring harness. It is OK to use the existing AK-450 wiring.
Note 3: Adding a new Buzzer to be mounted anywhere in the cockpit, i.e. Tie wrap into the aircraft Wiring Harness, or Fasten onto or behind the instrument Panel, or fasten on the Remote Switch Unit.

2. Register with NOAA (or IBRD) (or National) via on line, or mailing the Registration Form using the provided pre-stamped envelop.