If two people claim the same dependent, the tax filers must contact the Internal Revenue Service (IRS) support line to explain the errors, according to efile.com. The tax filers must mail another income tax form along with any additional required forms and the IRS conducts an audit of both returns and responds with a decision. The entire process can take from eight to twelve weeks.
Efile.com explains that if there is a dispute regarding who can claim the dependent, the IRS applies six tiebreaker rules. If only one taxpayer is the child's parent, the child is the dependent of the parent. If both taxpayers are parents of the dependent but file separately, the parent who lived with the child for the longest period claims the dependent. If the child lived with both parents for an equal period, then the parent with the higher adjusted gross income (AGI) claims the dependent. If neither parent qualifies to claim the child, the child becomes the dependent of the parent with the highest AGI. If either parent qualifies to claim but chooses not to do so, the parent with the highest AGI can claim the dependent. If unmarried parents live together with the child all year and meet all qualifying test requirements, then the parents may choose which parent can claim the child as a dependent.