macbook will not reset to different time zone ater travel????

To find out if it's system wide or user specific, try this...

Open System Preferences>Users & Groups, unlock the lock, click on the little plus icon, make a new admin account, log out & into the new account.

Does it work in the new account?

Can we assume that you're connected to the Internet? Is WiFi turned on?

Try SystemPreferences, Date & Time, Timezone, select adjust timezone automatically