To edit multiple users at once, use the batch edit feature in the Users tab.
Select the users you want to edit by checking off the box next to their name. You can select all users by checking off the box next to the "Name" title. Then select the "Edit Selected Users" button. A pop up will appear with user fields to edit.
You can change the media group (see the Media Group Settings article), enterprise (see the Enterprise IDs article), user status and delete users using this feature. The new information will completely replace the old user data. It will not be added to the old data.
Click the red "Update" button to update the user information.