I'm sure I've got something wrong here, but I just don't know what it is:

USE [master]
GO

DECLARE @LoginName VARCHAR(20)
DECLARE @Password VARCHAR(20)
DECLARE @SqlStatement NVARCHAR(MAX);

SET @LoginName = 'TestABC'
SET @Password = 'testabc'


--ALTER LOGIN TestABC WITH CHECK_EXPIRATION = ON
--ALTER LOGIN TestABC WITH PASSWORD = 'testabc' UNLOCK MUST_CHANGE

SET @SqlStatement = N'ALTER LOGIN [' + @LoginName + '] WITH CHECK_EXPIRATION = ON'
EXECUTE (@SqlStatement);

SET @SqlStatement = N'ALTER LOGIN [' + @LoginName + '] WITH PASSWORD = [' + @Password + '] UNLOCK MUST_CHANGE'
EXECUTE (@SqlStatement);

It errors with "Syntax error near Password"

Thanks