The Flexyfoot 'foot' is very easy to replace.
Firstly remove the old 'foot' by pulling it away from the collar until it clicks.
Then unscrew the foot anti-clockwise.
To fit the new 'foot' screw it in clockwise until it can freely rotate.
Then push the 'foot' in until it clicks.
Replace the 'collar' if it becomes damaged, the fit to the aid becomes loose or the 'foot' cannot be properly fitted. The 'collar' should be replaced with every third replacement 'foot' - fit a complete new Flexyfoot.