thanks for your help. It seems to be the only way calling an external program just to open another connection. Is little too much stuff, since I hoped, could be done within my oracle procedures.
Client side is VB and there I can run two connections concurrently while one of them is just used, to open a second short session for the already logged in user. The outcome would verify the “old password” is valid ( i.e. the right user is sitting in front of screen ) and then let user introduce a new password. Cost is one of the grace sessions, user can utilize for signon, before user’s account will be locked because of password expiration. I will hold the old password until the second login validates, cancel second session and then call oracle function to change password. This is due to increased security demands to hinder a unauthorized person changing somebody’s password who left the screen without having screen locked.
In my opinion the better way would hve been to do the check inside oracle.
Nevertheless, thanks for your efforts and have a nice day ( in old germany it’s now exactly midnight )