Can I modify an existing group?

Yes, There are three ways to modify and existing group:

From the Contacts application you can:  

1) Click the drop-down arrow on the VIEW button
2) Select the Groups, and then the type of groups you would like to view (Enterprise or Personal)
3) A list of Groups will then appear in the grid below with the options to share, modify, or delete.
4) Select the MODIFY button across from the group(s) you wish to modify.
5) From there you can add or remove contacts and click SAVE when finished.

-or-

1) Click the drop-down arrow next to View
2) Highlight Personal Contacts or Enterprise Contacts
3) Select the desired group
4) Click the drop-down arrow next to Actions
5) Click Modify Group
6) Make necessary changes ( rename Group add/remove contacts)
7) Click Save in the upper-left corner of the window

From the SImpleClick menu you can:

1) Right-click the Group name in the SimpleClick Window
2.) Click Modify Group
3) Make necessary changes ( rename Group add/remove contacts)
4) Click Save in the upper-left corner of the window

NOTE: Only users who have full access to Enterprise Contacts will have the option to add, modify, or delete these Contacts.  Access can be granted to individual users by the Enterprise Manager.