If you bought the extended warranty from the MS Store you could bring it in there.  If you didn't, you'll need to call Dell and have them replace the keyboard under the 1 year warranty.

I bought a XPS 13 9350 a few months ago and occasional the B and N keys on the keyboard don't work. If I press them twenty or thirty times then they start working. What are my options to get this fixed? It happens about once a day. It's frustrating. 

I live near the Mall of America, so could I bring it into the Microsoft Store that I bought it in? I'm just worried that if I try to demonstrate the issue that I won't be able to replicate it. Am I just stuck with an occasional malfunctioning keyboard? 

Thanks.

Occasional non-functioning keys -- what are my options?