Question : PACK TABLE

How can I do:
PACK TABLE table_name
in MS SQL??

Getting syntax error.

Answer : PACK TABLE

You'd shrink a db - and SQL Server should be doing that itself anyway (you can shedule them too if you want).
Try shrinking a db to satisfy your curiosity (as it sounds like this might be all it is :-).
Right click on the database in EM - All Tasks - Shrink Database.
Then see what effect it's had on your files.
But as has been said before - SQL Server should be doing a pretty good job of keeping on top of this by itself.