Change how many days before a password can be used over again
ALTER USER username
IDENTIFIED BY 'password'
PASSWORD EXPIRE INTERVAL number-of-days DAY
PASSWORD HISTORY number-of-passwords
PASSWORD REUSE INTERVAL number-of-days DAY
The Alter User command changes the password behavior for a user, there are 4 criteria that can be changed with this command each is done with a separate command
One of 2 ways to change the users Password
Change how long until the user must change their password
Change how many passwords before the user can use them over again