Since the time in the clock is delivered as data in your signal from the local wireless carrier transmitters, it cannot be altered.
Since we changed time settings to Daylight Savings early this morning, you should have noticed the correct changed time being displayed on your phone this morning.
However, you can change the Time Format on the V810 from 12 hour to 24 hour or "military time". First depress the menu key, (center top), then OK key, then scroll down to Initial Setup, then depress OK key. At Time Format depress OK key again and make your selection.