I currently have a 55x19 quartz countertop that has a small undermount sink. If I decide to reuse the countertop for a larger drop in sink could it be recut by a pro shop? What is the probability that this might crack (due to narrow margins left when the new cut is created)
You can take the unit to a granite shop and the shop will provide you with an answer like this.
"While it is possible to cut some quartz it is not a guarantee that it will cut properly. The possibility exist that the quartz will break or chip during the cutting process."
So if you are set on cutting it out - have it done .. and take the chance - if it does not work - buy a granite scrap piece.