David's response is the correct, thorough and appropriate one. However,
for a very small use case, such as an occasional task in another time
zone, I might suggest custom calculated fields on your form that take
your time and calculate it to other time zones – like you see clocks
in airports telling you what time it is in other cities. Have one field
for Pacific Time, one for Central, whatever and use a calculation to
alter the time from the original task appropriately. Please be warned, I
don...