You can amend your petition from divorce to annulment by withdrawing your first petition and filling out a new form, the same form as you used to file the divorce. But instead of dissolution, and check the box for annulment AND amended. There are also rules to follow after the amendment is made, such as serving the amended petition to your soon-to-be ex-wife. It is advisable to consult with a lawyer who is an expert in marriage status cases before attempting to take further action to avoid due process impediments, especially because there are distinct differences between a dissolution and an annulment case.