You can go onto the IRS Website (irs.gov) and print Release/Revocation of Release of Claim
to Exemption for Child by Custodial Parent it's form 8332. We had to do this with my son and grand daughter
her mom wanted to claim her but my son had her more than half the year so she could only claim a month or two and he took the rest. But you do need that release. Good luck
