Can you spray acrylic lacquer over urethane?
Keeping this in consideration, can you put lacquer over urethane?
If you are talking about spraying lacquer over the polyurethane and the poly is well aged, you might be able to get away with it by spraying light well-thinned coats of the lacquer. The safest thing to do is to use dewaxed shellac over the poly and then you can go to the lacquer without worry.
Hereof, can you spray lacquer over urethane primer?
You should be able to spray lacquer over the 2k urethane primer. You certainly can with PPG products. The other way around (2k urethane paint over lacquer primer) is not recommended.
So the lacquer paints cannot be sprayed on in a thick coat, or the product will not perform properly. Lacquer paints dry to a hard shell, leaving a very thin paint film. Lacquer can be over-coated with other lacquer, paints, or enamels and acrylics.