A Chapter 7 bankruptcy case may only be voluntarily dismissed after notice and hearing and only for cause. What this means is that creditors must be given an opportunity to object to your request to dismiss, and you must establish sufficient reason for dismissal.
While there is no definition of what constitutes sufficient reason for dismissal in the Bankruptcy Code, examples that courts have cited as insufficient include the debtor’s desire to re-file to include debts that have been incurred after the first case was filed or to avoid the liquidation of non-exempt property. Some courts, however, will allow dismissal where no creditors, after proper notice, object to dismissal.
Since there is no clear cut answer to whether or not you can voluntarily dismiss your Chapter 7 bankruptcy case, it would probably be best to consult an attorney to discuss your options and chances for success.