Normally it isn't an issue, because the corp picks up the fare, and I never buy a non-refundable ticket.

But I'd like to see my sister in Boston, and I noticed the cheap fares.

What do the following fare basis codes mean?

Where can I find if these are the upgradable fare basis?

Fare Basis Code: LE7FLY
Fare Basis Code: LX7FALL

(I was searching on expedia)