You can't! Get a different car or live with it!
On my 97 E250 I change the digital clock by pushing and holding the clock button in, then change the hour up or down with the search arrows on radio, and the minutes with the scan arrows .
change
Done one today... around three-quarters of an hour.
You Might Have To Buy A New One.
Press and hold clock button as your press seek arrow buttons for hour change. For minutes press and hold clock button as your press tune disc button.
Press and hold the volume knob in use the tune and select buttons to change hour and minute respectively
March 8
press and hold the clk button and change the hour and the minutes with the tune button!
UNPLUG THE BATTERY for an hour, or so.
Kick it or change the buttons in the back of the clock usually if you sit on it for an hour it will reset
If you have the "RDS" button push it twice for hour and press again for minutes. Use "sel" up or down to change each.
Press Clock button and hold then use seek and tune button to ajust hour and minute.