A complaint can certainly be amended and if this is done, it is called an amended complaint. Each state has its own rules on the time limits for filing an amended complaint, as do the federal courts. Sometimes after a complaint is filed, new facts or different facts are available, or the plaintiff wishes to add a different count. An example of this would be suing in contract and then adding a count to sue in tort. One issue that must be considered is that every cause of action has its own statute of limitations. So, in addition to having to follow the rules of civil procedure in each jurisdiction, an amendment to a complaint that provides a new count must be within the statute of limitations for that particular count. An amended complaint must be filed with the court and served on all defendants, and any defendant has the right to file an answer to the amendment within the time limit allowed in that jurisdiction.