STEP BY STEP INSTRUCTIONS for Setup: www.lifx.com/setup
If you've changed your Wi-Fi password, or setup a new router with a new password, there is only one way to reconnect the lights to the network.
You need to hardware reset them, and reconnect them, just as you did the first time.
Schedules and scenes will still work with the lights once reconnected. If you use the same light names, all other integrations should work as expected as well.