"Hey, Dylan! I just want to ask you: are remixes legal? I know you made a remix of “Can you feel my heart”, so can you tell me if its okay to remix this song I like?"
Try to get the OK from the artist before you do so. I’m sure you can without it, but it’s courteous to do so. If you plan on selling your remix, then you’re going to need permission from their record label. If they’re unsigned, then all you need is their permission.