Upgrade Macbook Pro Retina A1502 SSD I have an Early 2015 Macbook Pro Retina with a 128Gb SSD and 8Gb of RAM. I know I can't upgrade the RAM but I can upgrade the SSD. Will an Apple Store upgrade my SSD if I take my Macbook to them? Is it possible to know how much will it cost? Or maybe exchange my Mac for another one (same model) with a 512Gb SSD paying the difference?

I have seen this SSD in Amazon that should work for my Mac but if possible I prefer an official Apple Store to do the replacement. I'm asking because I will be traveling to NY and in my country they won't upgrade the SSD.
Yes, but I've heard Apple uses proprietary firmware on their SSDs (I could be wrong), however OWC does make SSDs specifically for the 2015 Retina MacBook Pro, so it appears they've figured out how to make replacements. Here's the link. I'm not affiliated with them, but have bought RAM and a replacement Mac battery from them, both of which work great.