Tom,

Anyone seeking a zoning change to a property must by law in accordance with the requirements for an amendment to the Chicago Zoning Ordinance, specifically Section 17-13-0107, notify all property owners of the application that live within 250 feet of the property to be rezoned.
Such a notice will contain conact information should you wish to object or find out more about the requested zoning change. A zoning Attorney would be the best person to advise you of your rights as a property owner and explain in more detail the specifics of the Chicago Zoning Ordinance.

Good luck, Ken.