I had a sink put in the bathroom and it does not drain well at all... when I called and asked the plumber why he stated that it was a gravity flow sink/drain. Is there anything that I can do to make it drain better or will I have to have a different sink put in?

is there anything that i can do to make it drain better or will i have to have a different sink put in?
Don't toss that sink just yet! Help is on its way.
Vessel sinks have no overflow to vent the drain so they require a special drain to drain properly.
You have a choice of vessel sink drains Pop-Up and Grid (see images) Pick the one you like. Good luck, Tom

Grannie...

Tom posted the solution above. Here, if your sink is manufactured like a vessel sink... no overflow hole... then it treat it like a vessel sink!

Have the plumber come back and install a flip top or pop top type of vessel sink drain. Stay away from the grid style vessel sink drains as they just don't work as well as the flip top or the pop top types... OK?

Mark