To edit a distribution list:
1. In Microsoft Outlook, click Address Book or use the keyboard shortcut (Ctrl + Shift + B).
2. Change the address book to All Distribution Lists from the drop-down menu.
3. Find the name of the group you wish to edit and double click.
4. Click Modify Members.
5. To add a new member, click Add. Select the people you want to add by double clicking them OR by selecting their name and click Add. Once the people you want to add are in the Add Bar, click OK. Click Apply to finalize your changes.
6. To remove a member, select the member you wish to remove from the Members list and click Remove. Then click OK. Click Apply to finalize your changes.