thank all for your reply.

In my case.
Some user have business trip between two branch with 1HR different time zone. They often think the time in PC is local time when they in business trip. this cause they miss some appointment.
I know the user had the sense of different timezone is more important. But as a engineer, I try to find whether is there a solution can be applianced for this case.
Yesterday, Microsoft support give me a reply that it is hard to do that. I thaught perhaps I need to end this idea.