Changing your P10 strap is a fairly easy process, below is a complete step-by step process of how to replace your ResMed P10 headgear.
Step One; Find the slit in your P10 headgear and grab your P10 frame.
Step Two: With the headgear slit facing outwards, thread the P10 frame through this slit and keeping moving it through to the end.
Step Three; You now need to pull the end of the headgear up and over the groove on the P10 frame.
Step Four; Your new headgear should now sit on your P10 frame as seen below.