In Multi-User, you can assign a different team member to a lead or showing when editing it on the ShowMojo Dashboard. You'll see a team member dropdown on the Edit Showing pop-over.

There is one critical constraint here. You can reassign the lead or showing to any team member who has that listing assigned to one of his or her calendars. Put another way: if a prospective renter couldn't schedule a showing with that specific team member, ShowMojo is not going to let you do it either.