Form 12509 Statement of Disagreement
Generally, when you have a disagreement and feel that innocent spouse relief should not be granted to your spouse or former spouse, completing IRS form 12509, Statement of Disagreement would be required.
Example of as to when it would be appropriate to file IRS Form 12509, Statement of Disagreement:
Your spouse or former spouse both co-owned a business together; both were active participants in the business. The business created a tax liability prior to your separation with your spouse or former spouse. Your spouse or former spouse files a request for Innocent Spouse Relief on IRS Form 8857. You strongly disagree that your spouse or former spouse should have any relief and should be fully responsible for the tax liabilities the business that both you and your former spouse have created prior to the separation. Completing a Statement of Disagreement would be appropriate.