A synonym is not dropped until you exit the Alter Table dialog box. Before you exit this dialog box, be sure you have made all appropriate changes and wish to save the table specifications.
To drop a synonym:
If you mark a Synonym name and then realize you want to keep it, before exiting the Alter Table dialog box, double click the name of the Synonym to display the Drop Synonym dialog box. Then click the Undo button. The - sign will be removed, and the original synonym will remain intact.