The need for a legal name change may result from marriage, divorce, adoption or simply a desire to have another name. Generally, you cannot change your name for a fraudulent purpose, such as avoiding debts. Means of changing your name generally include usage (in some states using a name as your own has the affect of making it your name); court order (a court order is recommended to change your name and is required by most states); or a marriage certificate as proof of name change.
The petition is filed in the District Court in the county where the Petitioner resides. A person is not allowed to change their name in order to avoid judgments or legal actions against him or her, or to avoid debts and obligations. A person can not change their name to defraud any person. For an order of name change to be granted, the court must find sufficient reasons for the change and also find it consistent with the public interest. A change of name upon marriage, dissolution, or divorce meets these requirements. Any reasonable objections made to the court may influence the court's findings as to whether the change of name is consistent with the public interest.
The name change process begins with the filing of a petition for name change in the district court where the petitioner resides. A hearing will then be held. If there are no objections filed with the court, the court may enter the order granting change of name.
Most entities will accept a legal name change order as proof of a name change in order to change records with that entity. Policies and requirements vary by entity, but I've yet to find a restriction particular to middle names.