It can be sold through a Realtor just like any other property. If you (or your Realtor) are able to take good photos, keep the showings to "real" buyers with your Realtor escorting them into the home and price it for investors, it could be sold as there are many investors looking for condos....one with a paying tenant even better!
The lease is still in effect so only those investors could purchase. As you get within 45 days of the end of the lease, then any buyer could purchase as their closing would take that length of time to finish.
The key is priced correctly! Let us know if we can be of some assistance.