You can't change the timezone shown in your Wet Ink class.
However, please note that Wet Ink shows in the time of the user.
This means, Wet Ink shows corresponding timezones to all participants in a class.
This helps to make sure that everyone is seeing the correct time and no one has to think too much about working out time differences.
For example, if an assignment is due at 5 PM PST - for students on CST time, this would be shown to them due at 7 PM (because of the 2 hour difference). Everyone will have the same amount of time to hand in an assignment or do tasks, this just might differ depending on where they are.