If your dependent was claimed when they should not have been, you can ask the other party to amend the return. If they will not remove the dependent, you may file on paper. The IRS will contact both parties to determine who is entitled to claim the dependent, and will credit the person that met the requirements. If it is determined that the other party should not have claimed the dependent, the IRS will make them pay back the exemption along with any penalties or interest associated with their false claim.