My key is broken. The white elastic plastic tear off. Help!

I'm going to take it to a third party apple store this evening. Should I change the whole uppercase or is a single key replacement possible?

I can't seem to attach the key back to the keyboard because the nylon part broke. However if I pressed it hard, the keyboard still works. That must indicates that the parts still function well.

Is it possible to have a key replacement and not dismantle the whole upper case?