If you can rightfully claim the dependent, you have confirmed the SSN is entered correctly and you wish to leave the dependent on your tax return, you will have to print, sign and mail your return to get it accepted. It will not affect the timing of your refund other than the longer amount of time it takes to process a mailed return.
Later in the year, the IRS will contact both parties who claimed the dependent to sort out who should be allowed to claim him or her.
