Summary: Panasonic KX-T7433 handsets, not sure which switch. No automatic summer time settings, so you have to do this to change the time. It may have to be done on the Admin handset – for us its the one that Night mode diverts to:
- Set date/time using digits and the right arrow soft key to move to the next section.
- Press Auto Dial / Store to store and then pick up the handset to cancel programming.
More detailed instructions here.