Pairing a BlueAnt ST3 to a new phone – gah! But I think this is what I did that finally worked:
Do what you have to do to get the phone ready to pair with a bluetooth device.
Power down the ST3. Power it up, holding the green button down. It will ask you to set the language again. Do that. Then it goes into pairing mode and automatically pairs with the new device. If it asks for the code, it’s 0000.