Issue
You want to set the same password again via udm:
udm users/user modify --dn uid=azimmer,cn=users,dc=schein,dc=ig --set password=univention
and you get a notification
Password has been used before. Please choose a different one.
Using the UMC you have a checkbox Override password history. This checkbox flag is only valid for this one change.
Solution
You can use the "Override password history"flag in udm as well. In udm it is called overridePWHistory
udm users/user modify --dn uid=azimmer,cn=users,dc=schein,dc=ig --set password=univention --set overridePWHistory=1
You can also disable the passwordhistory. It is a default policy. You can list this policy via udm
udm policies/pwhistory list
or via univention-ldapsearch:
univention-ldapsearch -LLLo ldif-wrap=no -b cn=pwhistory,cn=users,cn=policies,$(ucr get ldap/base)
Environment
The above is only valid for full-fledged users, not for simple ldap or address book accounts. For these type of users see article.