To change the time on the Panasonic KX-TD Series (308, 816, 1232) you must first
locate the lowest numbered extension in your system it will be extension number 11
for the KX-TD 308 and extension 101 for the KX-TD 816 and KX-TD 1232.

At that extension  press the program button (if your phone does not have a program
button press the "Pause" button.  Then dial * * 1 2 3 4 and the display will show
"USR PRG NO?".  Here enter 000.  The display will show 000 DATE / TIME.  At this
time press the SP Phone button twice and the time will show on the display with the
Hour blinking.  Enter the new hour then press the "FWD/DND" button; enter the
minutes then press the "FWD/DND" button; to choose AM or PM press the "AUTO
ANSWER/MUTE" button; then press the "FWD/DND" button; to choose 12 or 24
hour display press the "AUTO ANSWER/MUTE" button.  Then press the "AUTO
DIAL/STORE" button to enter the new time.

Do not forget to press the "PROGRAM" (or pause) button to get out of programming.

All display sets will now show the new time.