This summary is not the rule. The rule text controls.
If you filed an appeal and change your mind, you can ask to drop it. This is called a voluntary dismissal. To do this, everyone involved in the appeal needs to agree on the terms, or the Court will decide the terms for you. In short, you can't just walk away without either working it out with the other side or getting the Court's sign-off.
The other side of this rule deals with situations where the person who won in the lower court (called the appellee) wants the appeal thrown out. They can file a motion to dismiss at any point during the appeal, for any legal reason. A common reason is that the court doesn't have the authority to hear the case in the first place. This rule also gets rid of something called a "motion to affirm," which used to be a way to ask the court to simply uphold the lower court's decision without dismissing the case. That option no longer exists under this rule.
