To change the collar ID on the Astro 430 please follow these steps. You Must be connected to a collar in order to change it's ID.
  1. Start at the main menu
  1. Select "Dog List"
  1. Select the dog collar you wish to change the ID on
  1. Select "Show Info"
  1. Press the menu button on your device -
  1. Select "Change ID"
  1. Now you can select which available ID number you wish