If you read my blog post about the #1 Common Painting problem, you would have learned that people put latex paint over oil based paint and have to deal with the consequences down the road. The main problem is the painter did not identify their surface prior to painting. Once you identify that the paint you are about to use is oil based, you do the following steps

*Lightly sand entire surface
*Apply (1) coat of an oil based primer: If over wood, I prefer a Sherwin Williams Oil Based Wood Primer
*Once dry, sand lightly
*Clean dust and debris
*You can now properly apply your choice of latex paint

This is the proper way to convert your oil based paint into latex paint!!!