Comma vs. decimal

[Mark]

Somehow I mistakenly reversed the use of the decimal and comma in
displaying a number. I refered to the original HP 12C manual for
guidance and unfortunately this does not reverse the selection
process. Any recommendtions?

[Dr. 88 Keyz]

1. Press the "ON" key to turn off the calculator. Note: the
calculator must be off in order for step 2 to work.
2. Press "ON" and "." together to toggle the decimal/comma displaying
a number.