By default, all users in Dynamics 365 should be able to change their time zone in their personalization settings, regardless of their license type. It's possible that there is a specific security role or customizations in your organization that are preventing team members from changing their time zone.
To troubleshoot this issue, you can try the following steps:
1. Check the security roles assigned to the team member who is unable to change their time zone. Make sure that they have the "System Administrator" or "System Customizer" role, or a custom role that has the "Write User Settings" privilege.
2. Check if there are any customizations or plugins in your organization that are preventing team members from changing their time zone. You can do this by temporarily disabling any customizations or plugins related to user settings, and then check if the team member is able to change their time zone.
3. If the issue persists, you can try resetting the user's personalization settings by going to Settings > Options > Personalization Settings, and then click the "Reset to defaults" button. Note that this will reset all of the user's personalization settings, not just the time zone.
As for a workaround for the issue with appointments, one possible solution is to set the time zone for each appointment explicitly when creating it, rather than relying on the default time zone of the user. You can do this by clicking the "Time Zone" button in the appointment form and selecting the appropriate time zone. This way, even if the team member's time zone setting is incorrect, the appointment will be displayed at the correct time.
