Appropriate commission percentage if tenant is buying

Hello BP experts,

I have a rental property that I was going to put on the market to sell and I have a realtor/agent that I have aligned to work with me on this transaction.  However, my tenant just informed me that he is interested in potentially buying it from me.  In this case, how much percentage is appropriate for commission as my agent doesn't now have to do all the work associated with listing/marketing/showing?  What are your advices in this scenario?  Thank you!