Tenant wants to buy?

[Miranda Crown]

After a brief stint on the sales market last fall, we opted to rent out our home for 6 months and then return to the market this spring (our tenants were/are fully aware of these circumstances). In any case, we just met with our realtor, signed a contract to place it on the market 4/1/14 and the tenants are now interested in buying. Obviously, we would all love to avoid paying commissions but I assume we are too late? Any suggestions on how to navigate benefit both parties? I always appreciate the wealth of advice on this site! Thanks