Ideally you should be providing the source time zone information to the database as you load the data (and optionally storing the time zone offset). Then when you run a query you can specify (in the query, at session level, at user default level, or at system default level) the time zone used for the result set column. Internally the data will be handled as UTC.
If you neglected to note or adjust the time zone when you loaded the data, you will need to figure out how to let the database know the original time zone offset before you can ask to see it "AT" some other time zone.
The relevant dbscontrol fields are TimeDateWZControl, System Time Zone Hour, System Time Zone Minute, and/or System Time Zone String (which is actually set using tdlocaledef). But before changing any of these settings, especially on an existing system, please contact Teradata for assistance. Careful planning is required to assess the impact of such a change and mitigate any unintended side effects.