How to remove a bathroom sink form the base cabinet?

look under sink for clamps and unscrew, if epoxied down just remove the sink if out dated lay paper or drop cloth and bust it out

Nivasi is correct, look for any screws and clamps. Remember Righty tighty, Lefty Losey.

You'll need an adjustable wrench, #2 Phillips or Flathead screwdriver, utility knife with sharp blade, thin pry bar or stiff putty knife. Bucket and old towels

Turn off the water under the sink, where the hoses are going to the hot and cold water taps. Remove the hoses, remove the p trap letting the water drain hopefully into the bucket. But that’s why you have the towels... It’s easier to remove the faucet, handles, drain after you get the sink out. If you’re not keeping any of it, think of donating to Habitat restore.

Look up and and see if you can see any screws and clamps holding the sink to the vanity. If you see any, check the type of screws, in the US it will be either a #2 Phillips or a flat edge. Don’t use the wrong size Phillips driver or you will cam out the head. If there are any, there will probably be four, two in front, two in back and the clamps will probably be some type of plastic. After removing the screws, see if you can lift the sink. If you can great! If not, take an utility knife to cut the caulking, once you get it started, a stiff putty knife might help to wedge under or a very flat thin pry bar. But if your sink covers the entire cabinet, it’s probably just sitting on it. If you have tile, laminate, etc around the sink go to the utility knife..I have a pry bar that’s my go to tool for almost everything from removing molding to prying. it’s a bit less than a foot long, flat on one end, angled on the other. If the cabinet and sink are old, it could just be the weight and gunk. Rock a wee bit left to right to see if the sink is free, be gentle so you don’t damage the cabinet. There may be about 1/8 - 1/4” play. It is probably being held by a metal piece screwed to the wall so the sink has to be lifted straight up right along the back wall. You won’t see the hanger until you lift the sink off. If you can show a picture, we might be able to help better.