USE TEMPDB
GO

CREATE QUEUE myEventQueue
GO

CREATE SERVICE myNotifications 
   ON QUEUE myEventQueue
([http://schemas.microsoft.com/SQL/Notifications/PostEventNotification])
GO

-- hook it up to alter table...
CREATE EVENT NOTIFICATION myEvent
ON DATABASE
FOR ALTER_TABLE
TO SERVICE 'myNotifications', 'current database'
GO

ALTER TABLE T1 ALTER COLUMN x BIGINT
GO

SELECT * FROM myEventQueue
GO

SELECT CONVERT(XML, message_body) 
 FROM myEventQueue
GO