You can specify a different default session calendar for a user by specifying the desired SET SESSION CALENDAR SQL text string as the startup string for the user by submitting an appropriate CREATE USER or MODIFY USER request.
Assuming that the default business calendar for the site is Teradata, the following CREATE USER request creates a user named pkk and uses the STARTUP string for pkk to set his session calendar to COMPATIBLE instead of Teradata each time he starts a new session.
CREATE USER pkk AS PERM=10E6, PASSWORD=pkk, SPOOL = 1200000, FALLBACK PROTECTION, STARTUP=’SET SESSION CALENDAR=COMPATIBLE’;