Full_Name: Version: 2.4.26 OS: URL: Submission from: (NULL) (18.104.22.168)
pwdAllowUserChange This attribute specifies whether users are allowed to change their own passwords or not. If pwdAllowUserChange is set to "TRUE", or if the attribute is not present, users will be allowed to change their own passwords. If its value is "FALSE", users will not be allowed to change their own pass- words.
Given this text I'd expect that admins can still set the userPassword attribute. Such a policy is often used for system/machine accounts where the machine entity itself does not have to change the password but an admin should be allowed to do so.
By reading the code, I note that pwdAllowUserChange is not checked when the operation is performed by the rootdn, which in many senses can be seen as an administrator. If by administrator you mean a generic user that is logically granted administrative privileges (e.g. limited to this purpose) I concur it is not possible currently.
By reading the man page (and the draft), this attribute seems to be essentially intended as a replacement (a workaround for the absence) of access control. So you could avoid setting it, and use ACLs instead.
OTOH, by strictly interpreting the way its use is discussed in the draft, it should only apply to attempts by "self" to modify the password, so a modification performed by a different identity (provided ACLs permit it) should not be affected.