1. Definition & Purpose The sidchg (Session ID Change) key is an attribute that can be specified on a RACF user profile (or similar mainframe security product). When activated, it allows a user to change their own session ID (also known as the ACEE — Accessor Environment Element — or terminal session identifier) without requiring a full re-authentication (re-login).
ALTUSER userid SIDCHG To remove it:
ALTUSER userid NOSIDCHG It can also be specified during initial user creation: sidchg key