To switch to different compatible, paired Bluetooth headphones when playing music on Apple Watch:
- When viewing the watch face, swipe up to open Control Centre.
- Scroll to the bottom of Control Centre and tap on the name of the currently active headphones.
- Select your preferred headphones.
To unpair Bluetooth headphones:
- On your Apple Watch, go to: Settings > Bluetooth.
- Tap on the "i" / info next to the headphones that you wish to forget.
- Tap on Forget Device.