Cannot Alter Table Being Used For Replication

If you have a table you wish to change that is being replicated you may have trouble changing it and get an error saying that Cannot alter the table 'Table Name' because it is being used for replication.

To get round this  I stopped the replication job then tried to change the table through management studio but this still failed.  I then opened a query window and tried to alter the table with a script 

ALTER TABLE table name ADD column_b VARCHAR(20) NULL ;

 and bingo it worked.