Purchasing property with existing tenant

[Michael Jones]

To preface this question, I am located in Chicago.

I am interested in putting an offer on a condominium (short sale) with an existing tenant. The tenant's lease expires in about a month, and I would like to close on the property after the tenant has vacated the property. However, I would like to put this as a provision in my contract offer. Has anybody had any experience in doing something like this? I assume I would include an addendum with my offer which states that the my offer is contingent on the current tenant vacating the property upon close? If anyone has a good example -- of the rhetoric for this -- that they could refer me to, I would greatly appreciate it.