You may be able to do a revocation of release of claim to an exemption. IRS Publication 17 says that the custodial parent can revoke a release of claim to exemption that he or she previously released to the noncustodial parent on Form 8332 or a similar statement. If the custodial parent provided, or made reasonable efforts to provide, the noncustodial parent with written notice of the revocation in 2009, the revocation can be effective no earlier than 2010. The custodial parent can use Part III of Form 8332 for this purpose and must attach a copy of the revocation to his or her return for each tax year he or she claims the child as a dependent as a result of the revocation.
