My wife and I divorcing. Most income & tax payments come from her. We used to carry over refund as credit towards next year. How would I shift it to my wife's upon split

I am primary on return but income most from her. I could cash out the refund but since she is Self-Empl and I did not compensate for cashout, she may be facing an underpayment penalty if the refund next year carryover is not applied.  Is there a way to tell IRS to apply credit to her part ?