Not easily. You need experienced bankruptcy counsel. It needs to be determined if there is cause for you to consider a chapter 11 or if you are better suited for a chapter 13. To convert a case after the trustee finds assets can be difficult and the trustee can object. The conversion must be in good faith. If you were to succeed and sell the houses your self you would not get the commissions. Please find an experienced bankruptcy lawyer quickly.
Conversion will require a motion showing that in fact you qualify for chapter 11. You need to consult a chapter 11 attorney. Your other options are to contest the trustee's action to sell the properties in chapter 7, file a motion to dismiss the case and offer to pay the trustee for his time spent on the case (this worked for one of my clients), or allow the properties to be sold.