So, there's no sound coming out of my right earbud. I'm still under warranty so I can get it replaced for free. However, I'm not exactly sure how to go about that. I can do it online, but I'd prefer not to have to go and ship out the original. Considering I'm picking up my Mac from the Genius Bar this week, I want to swap my earbuds there. But do I need to set up a separate Genius Bar appointment to get them swapped, or can I just get them swapped out while I'm there? Also, will I just need to have my iPhone's serial number as proof of purchase?