You can change both the WebAdmin timezone, as well as your Account's time zone directly through the WebAdmin.
Adjusting the global WebAdmin Timezone
Please note: you must be an Admin in order to access WebAdmin Settings.
To change the time zone for the entire WebAdmin, navigate to Administration > WebAdmin Settings and in the 'General Settings' section you can adjust the Default WebAdmin TimeZone setting:
Adjusting your Account Timezone
Any SysOp or Admin Account can perform the following action
To change the time zone for your Account, navigate to My Account> Preferences, choose the 'Settings' Tab and adjust the Timezone setting.