Editing/Deleting phrase set-to-attribute assignments?

Program RC161AWM (EHS - Specification Database Structure - Settings for Value Assignment - Generate Standard Phrase Sets) will

generate standard phrase sets for all characteristics of data type CHAR 30.

Assistance on this program also indicates that:

If you do not want to generate a phrase set for a characteristic of type CHAR 30, you must delete this assignment in the phrase set-to-attribute assignment after the standard phrase sets have been created.

OK, but I don't see where or how to edit or delete the phrase set-to-attribute assignments. There is not customization activity. Also under CG12, its possible to perform Phrase Management. However, you can't delete a Phrase set or change the phrase set-to-attribute assignment.

Thanks for help in advance,