ChangeAccountPassword Method
The ChangeAccountPassword method of the SPUtility class changes an account password for the specified SharePoint site.
Parameters
web A Microsoft.SharePoint.SPWeb object that represents the site.
loginName A string that contains the user name of the user.
oldPassword A string that contains the old password.
newPassword A string that contains the new password.
Requirements
Platforms: Microsoft Windows Server 2003
Security: Code Access Security