First, what you propose to do is a crime. In and of itself. Even if you and your wife paid for the tickets out of personal funds and swap tickets just for fun.

Second, what you propose to do here is a fraud and income tax fraud because your employer will likely deduct the cost of the ticket as a business expense. If your wife is using the ticket, the expense is not deductible and you must report that to your employer and the employer needs to back the cost of the ticket out of its accounting system.

Third, what you propose is a fraud under the terms of the contract with the carrier.

Real world? Will anybody go to prison for this? Not likely. But, you asked the question of what could happen. More likely if you get caught is being released after a chat up by the cops, an unpleasant episode with your employer (unpleasant TBD by your relationship with your employer), and then a bit of self-reflection about this.