At a guess - and that's all it is - you're going to see an amount associated with this cancellation agreement included in your W-2 Box 1 amount. That's how a "nonqualified" sale of stock acquired via an ISO is handled and I expect that will be how your situation is handled, too. If you don't receive a 1099-B for the sale, and you likely will not, then entering your W-2 "as it reads" should cover all the necessary reporting. If you do happen to get a 1099-B too, then you report that on your income tax return. Properly done the 1099-B should result in no material gain or loss, (a small loss due to commissions and fees is common), resulting in no "double reporting" of income.
The devil is in the details with these things and you'll want to see how the company reports all this to you, first.
