Withdraw your election to be taxed as an S corporation with the IRS. Draft a letter to the IRS requesting that your S corporation election, made when you filed IRS Form 2553 - Election by a Small Business Corporation, be withdrawn. State the effective date of the withdrawal. Send the letter to the IRS service center that processed the original election request.
Download IRS Form 8832 - Entity Classification Election - from the forms section of the IRS website. Fill out the form, following the instructions provided. Indicate, as directed, that you are changing your tax structure designation from corporation to sole proprietorship. Sign and date the form.
File Form 8832 with the IRS by mailing or faxing it to the address or fax number provided on the form.