Everything in ActiveDEMAND is timezone agnostic. The platform is 'viewed' through the user's configured timezone. Each user account has its own timezone.
Setting Your Timezone
Click your username in the top right toolbar, and edit your timezone in the profile settings.
Setting An Employee's Timezone
To change a user's timezone, either edit the user account (if you are admin) by clicking on the edit button (pencil) (Administration->Account Settings->[Employees]), and selecting the time zone from the drop-down list.