Changing password expiration date

How do I change a user's password's expiration date? The information is somehow stored in the sys.user$ table and the sys.dba_users view pulls information from there to construct a EXPIRY_DATE column. However, the view is built using 5 levels of nested decodes which is difficult to understand and I'm afraid of messing something up when playing around with sys.user$.

Using Oracle8i Enterprise Edition 8.1.6.1.0

-Jens Received on Mon Oct 29 2001 - 21:36:39 CST