I'm selling, tenant wants to stay longer. What do I do?

[Victor Noriega]

We have a investment property in Austin. The current tenant has been there for 2-1/2 years. We had told the current tenant last year that we intend to sell the property and had offered it to them at a discount. They said they needed to fix their credit but they also wanted a bigger home. 

Prior to the lease ending, they said they wanted to stay another 3 months. We gave them a verbal approval and sent them the 3 month lease to sign. They did not respond for three weeks and in the middle of May, they asked to meet for the signatures. By this time my wife and I noticed that the economic conditions had changed and the CMAs were a lot higher then we had anticipated. We confirmed with a realtor. 

Well the lease is up on May 31st and we allowed them to go month-to-month with the lease ending on June 30th. We are placing the home on the market on June 2nd. 

The tenant has been approved to buy a home. This is great news, I thought. Now the request from the tenant is to stay until August 10th because that is when their new home will be ready. 

I want to sell it as soon as possible. What are some options?