Your site should not be designed in a way that makes something like this possible in the first place...
You should not store passwords. They should be salted and hashed; the password itself should never be saved or printed anywhere.
Your admin should not be able to view or change passwords, either. If someone wants to change their pass, they should do it themselves, from their own CP. If they lose their pass, they should be able to "reset" it (typically via email).