This password can be changed in 'schconfig' from the DOS/UNIX command line/shell.
C:\>schconfig
Copyright (c) 1997-2006 Oracle Corporation, All rights reserved
***** Delivers Configuration Menu *****
1 - Configure Scheduler
>>> Enter Choice: 1
***** Scheduler Configuration *****
1 - Database
2 - General
3 - Advanced
0 - Quit
>>> Enter Choice:
>>> Enter Choice: 2
***** Scheduler General Configuration *****
10 - Administrator Name : Administrator
11 - Administrator Password : *****
0 - Quit
>>> Enter Choice: 10, then 11
0 - Quit
0 - Quit
0 - Quit
Quit 3 times and restart all Analytics Services (to bring them back in sync - restarting the BI Scheduler on its own also works, but Job Manager connections may exhibit stale behaviour depending on what has been changed) .