>I finished a bowl yesterday and put lacquer on the bowl, while I've had some success in the past with lacquer, I don't like the finish I got this time. Instead of trying to sand it off, can I put polyurethane over the top of the lacquer.
what is it you don't like? You should be able to achieve virtually the same finish with lacquer that you can with Polyuethane except for color and hardness of finish. If it's gloss you want simply build up more layers. How you apply it also changes the appearance.
Personally I don't like the color that Poly adds to wood so I switched years ago to lacquer or shellac. I still use it for table tops when I make things for kids because it takes more abuse.