Painting - Pealing paint

I just purchased a home that the trim had just been painted with a high gloss latex paint. I noticed a scar in the paint and when I pulled at the paint edge in pealed off like a sunburn. I was told by an employ at Home Depot that it was probable painted over oil gloss paint. Is there a product, undercoat etc. that will penetrate the latex paint and cause it to adhere to the original oil base paint or do I have to peal off all the latex enamel paint before I recoat it?

You have answered your question.There is nothing that will cause the peeling paint to bond.If it's tough to remove in places a heat gun is very helpful.