Sign on bonus repayment

Had gotten payment for sign on bonus in Jan 2025. Left job in November so had to prorate and pay a portion of it back. Paid $17K in December of 2025. 

Been trying to get ahold of someone at old company to adjust W-2 for 2025. But they are so disorganized that I’m not confident they will be able to adjust in time. 

 

I’m wondering what I would have to do to adjust down income manually so we don’t end up paying taxes on that $17k unnecessarily.