Change User's Domain for Windows Authenticated Users

USE [TeamPulse]
    GO

    DECLARE @Domain nvarchar(128) = 'PROGRESS' /* CHANGE THIS to the DOMAIN that the new user will use*/
    DECLARE @OldDomain nvarchar(128) = 'TELERIK' /* Old domain that user was using */
    DECLARE @UserID int = 42 /* CHANGE THIS to the UserID (from the User table) of the user that is being converted */
    DECLARE @AspnetUserID uniqueidentifier
    DECLARE @Username nvarchar(256)

    /* Get the current user's information */
    SELECT
     @AspnetUserID = u.StsUserID,
     @Username = u.Username
    FROM [TeamPulse].[dbo].[User] u
    WHERE u.UserID = @UserID

    /* Modify user in User table */
    UPDATE [User]
    SET Domain = @Domain,
        Provider = 'Windows'
    WHERE UserID = @UserID


    /* Modify user in aspnet_Users table */
    UPDATE [aspnet_Users]
    SET UserName = @Username + '@' + @Domain,
        LoweredUserName = LOWER(@Username + '@' + @Domain)
    WHERE UserName = LOWER(@Username + '@' + @OLdDomain)