We picked up a neat looking glass top table with rattan/wicker chairs. It was a steal so we bought it even though the glass on the table is too long. Can a glass shop cut it down?
Of course, guys cut window glass all the time to fit people's windows. They even cut mirrors & bevel. So you can get a glass cutting tool at home building store or take it to any hardware that cuts glass & they will charge you few bucks to do it. Several ways to smooth the edge but you want it to match the rest. If it fits down in a "groove"(table has an edge around it with piece all around that glass sits on so most of glass is down & hidden on edge even so use some wet/dry sandpaper on block of wood to smooth glass so no 1 gets cut as glass is very sharp. Just as you could use emery board to file off chip on grandma's 100 yr old china, you can smooth this edge but if glass cutter can do it let him, you might save yourself some cuts. Painful until you get it smooth so won't cut you at all. If glass sits on top it is little more tricky & corners need care so you don't damage top. Good Luck!
If the glass is tempered as most table tops are it can't be cut after it's been tempered.
Yes, its a very easy task in the hands of an experienced person who knows how to cut and has the equipment with which it can be cut. Glass cutting is very simple.
Here is a link that might be useful: One Day Glass