Parties to a lawsuit generally have an absolute right to nonsuit (dismiss) their own claims for relief at any time during the litigation until they have introduced all evidence other than rebuttal evidence at trial.
In Massachusetts, parties to a lawsuit have the right to voluntarily dismiss their own claims, which is often referred to as 'nonsuit.' This right is not absolute, but it is generally available to a plaintiff before they have rested their case at trial, meaning before they have presented all of their evidence, except for any rebuttal evidence. The relevant rule in Massachusetts is Rule 41 of the Massachusetts Rules of Civil Procedure, which outlines the conditions and procedures for voluntary dismissal. A plaintiff may dismiss an action without a court order by filing a notice of dismissal at any time before the opposing party serves either an answer or a motion for summary judgment. After this point, a case may be dismissed only with the court's approval, and such approval may come with conditions. Additionally, if a plaintiff has previously dismissed a case in federal court or in another state's court, they may not be able to dismiss the action again under certain circumstances. It's important to note that the right to nonsuit can be affected by other factors, such as counterclaims by the defendant or stipulations made by the parties.