You can define/update/delete TPX users with Administrators in TPXADMIN. If you are also using STX some users might also have been defined a STX-structure. To find out which users are defined for TPX and STX use this TPXBATCH-Job:
//EXTFILA DD UNIT=SYSDA,SPACE=(CYL,(1,1)),DISP=(MOD)
//RPTFILA DD SYSOUT=*
//SYSIN DD *
EXTRACT GIVING(EXTFILA) USER AND NO SESSIONS (VUSR$TPX(Y) XU$STX(Y))
SET RTITLE1 '1USERID'
SET RTITLE2 ' ------'
REPORT GIVING(RPTFILA) USING(EXTFILA)
((' &UIDXNAME'))
The result is a list of all users having both, TPX- and STX-definitions looking like this:
USERID
------
ADMINA
NVIADMIN
XXUSER