In Texas, a modification of a custody order refers to a legal process by which the terms of an existing custody order are changed. This process can be initiated by either parent or guardian, and may be necessary if there has been a significant change in circumstances that affects the welfare of the child. For example, if one parent is moving out of state or if there are concerns about the safety and well-being of the child with the current custody arrangement, a modification may be necessary. The process of modifying a custody order involves filing a petition with the court and attending a hearing, where the judge will consider the evidence and decide whether a modification is in the best interest of the child.