Can you upgrade the RAM in the latest MacBook Airs if you ship them to Apple themselves?

I know that RAM is soldered onto the mainboard on the latest MacBook Airs, which makes a DIY upgrade apparently impossible. But would Apple do it instead though?

The guy at the Apple Store told me that I could send the Mac back to Apple and they could upgrade the RAM, but he didn’t look very convinced if I must be honest, so I wanted to double check here.