Create user defined server role

Hi,

Could anyone help me out.

I want to create a user 'passadmin' the user must be defined a server role so that the user can only change the password for the other users(logins). My environment holds all sql server 2000,2005,2008,2008r2, 2012. what type of server role can be provided. Since that user holds security admin as of now(but the customer wants the user to edit logins not to delete or create users(logins)).

Thanks.