convert a cmyk logo in pantone

I have a cmyk colour logo and I want to convert it in pantone colours. There are some gradient taht i can't convert because gradient make a grey part between the 2 pantone colours. I need a professional printer tthat have really an experience with pantone converion from cmyk. The print result must be as I see in illustrator. I have the .ai file in cmyk. There are other project like this in future. regards, MDesign C.S.