Surrogate user authority is the ability to start work on behalf of another user. If user A has surrogate authority for user B, then user A can start a task that runs under user B’s user account.
By default, users do not have surrogate authority. You can specify that all users are granted surrogate authority. Enterprise Server for .NET does not currently let you selectively grant surrogate authority either to or for individual users.
Surrogate authority allows users to specify any recognized user name in the USERID parameter of the EXEC CICS START macro: EXEC CICS START USERID(. . .)
See the CICS documentation for more information on surrogate users.