Redrawing lot lines on 2 pins, expense and timeline?

[Davis C.]

I'm looking at a property in northern Cook county with 2 pins, each about 5000 sq ft. 50x100. The house has a garage, that puts it over the dividing line by 5 feet. I was thinking I could have the lines redrawn, so I could sell the empty lot, or possible develop on it. 

Just looking for any advise/info on this process before making an offer.

[Vincent Incopero]

@Brie Schmidt Because the 2 PINS are essentially useless individually and the property straddles the two, the expense of merging/consolidation of the 2 PINS is just that, a wasteful PITA