You can change your time zone at any time in Microsoft Outlook. Changing your time zone in Outlook is equivalent to changing it in Windows Control Panel. This affects all times displayed in Outlook as well as times displayed in other Windows-based programs. You can also add and display a second time zone in Outlook, which is useful when scheduling meetings or conference calls with people in other time zones.
In these cases, the meeting organizer's time zone is the reference point. If you organize a meeting and display free/busy time for invitees from other time zones, their busy times adjust to display correctly in your time zone. A second time zone is visible only when viewing days.