Sorry that my explanation wasn't clear. If I change the Time Zone from Admin -> Location, the displayed time does not change.
I think this is because changing the Time Zone from Admin -> Location is not changing the value of time that's already been saved.
If I add an new entry, the time will now be saved using the new Time Zone. So, I'll have a mixture of time from the previous time before I made the change and from those after.
I was wondering if there is any way to convert the previously saved time to the new time zone.