So.

Lets assume that I am getting a pink drop from the boss.

Does the re-roll take part in this and if it does how will it change the drop? If it takes part in it would it change the item to more rare item?

If I had as for an example Vampiric Leather, would it be changed into Sanguine Leather? Or is it changing randomly to even more rare pink? Or just randomly changes into other pink?

I would be pissed if I had Sanguine Leather and it changes into pilgrim hat.

Just asking because I am considering to try it but I would love to know if it actually helps.