Jobs can NOT be renamed on the Connect Management Console, but technically you can rename the Synchronization job folder on an agent. Note that in this case the renamed folder will cease syncing on the agent, and the old_name_folder will be re-downloaded from the Server upon agent restart and will continue syncing with others.
When renaming a Selective Sync folder: the flow will be the same, but all placeholders will be removed from old_name_folder.
Groups can be renamed. To do so, click Groups > Select the group > Edit:
Once the group is renamed, click "Save".