A motion to dismiss a bankruptcy case is a much more formal process and can be filed by the bankrupt debtor itself or an interested third party.
When a debtor in a bankruptcy case is the party requesting dismissal, it usually cites a lack of assets and a likelihood that no plan for distribution of assets to creditors could be confirmed in the case.
Other parties requesting dismissal often argue that the debtor has not made enough progress to resolve the case or that negotiations to settle disputes are at a dead end.
In a Chapter 11 case, an alternative to dismissal is conversion of the case to Chapter 7 bankruptcy. Here, a trustee is appointed to identify and liquidate any assets and distribute those to creditors. After that process is completed, the case is usually closed.
In a dismissal, the debtor pays what administrative and priority claims it can before the case is dismissed, and other creditors usually get nothing.