How Can A User Change Password In SQL2005 Via TSQL?

I have an application that controls user logins, passwords, etc. at the front end for a SQL database. I am in the stage of migrating to SQL2005 and cannot get the TSQL code to allow a user to change their own password. Here's the background;



The ADMIN of the app is a Sysadmin on the SQL server and can create logins, set roles, etc. Assume the Admin creates a user TOM with a password of xxxx. This works fine using the create login statement from a Connect.Execute statement from my app like so;



"Create Login 'TOM' With Password 'xxxx', Default_Database = 'myDB', Check_Policy = OFF"



TOM will be setup with db roles as well



When TOM logins into my app, he will have to change his password at some point. The TSQL code I am using (which fails) is executed by TOM who has a connection to the SQL db because he is logged into the app.



"Alter Login TOM With Password = 'xxxx' Old_Password = 'xxxxx', Check_Policy = OFF"



At this point I get an error:


RunTime error -2147217900 (80040e14)
ODBC SQL Server Driver][SQL Server] Cannot alter
the login 'TOM', becuase it does not exist or you do
not have permission.

Obviously it exists since TOM is currently logged into the SQL Server. So if it's permissions related, what permissions does a user need to change his/her password? Or is there another way to do it?

Thanks in advance for your help.

CH