change to session_user in a security definer function

Hi list,

I wonder if it is possible to do so?

eg: security definer function checks session_user privileges against a table
(or whatever) and call another function to create a prepared statement AS if
it was session_user making that call.

JY
--
One does not thank logic.
        -- Sarek, "Journey to Babel", stardate 3842.4