Canon 0585C006 Instruction Manual page 82

C / >: Setting Custom and Personal Functions
Clearing All the Custom/Personal Functions
Even if you clear all Custom Functions, C.Fn-00 will not be cleared.

P.Fn-03 and 07 are not displayed on the Speedlite 430EX III.

You can set or clear all Custom Functions of the Speedlite on the camera's
menu screen (p.44).
82
You can clear all Custom Functions or
Personal Functions by selecting
<C> or <D> on the screen on
the left, and selecting <;>.