If you have to deal with clients in other time zines, there are several things you could do to advertise this fact to your customers:
- go to "My Account" > "Company details" and add you time zone information there in the "description" field. Something like "Please note ALL TIMES are PST".
- add the same notice to the appointment type's description and/or field (under "My Setting" > "Appointment types" > "Review & make changes"). This will also show up on the notification emails and reminders.
- include it in the "thank you message" for the appointment type. This will be shown to your clients after they have made their appointment (so they can promptly cancel it and make a new one in case they didn't see the other warnings) and it will also show up on the first notification email at the very top.
- include it in your email reminders.
- if you do have a website which clients first go to before actually booking anything.. add it there as well.
  and  should be configured under "My Setting" > "Appointment types" > "Review & make changes".