§1. A member in perpetual vows cannot transfer from one religious institute to another except by a grant of the supreme moderator of each institute and with the consent of their respective councils.
§2. After completing a probation which is to last at least three years, the member can be admitted to perpetual profession in the new institute. If the member refuses to make this profession or is not admitted to make it by competent superiors, however, the member is to return to the original institute unless an indult of secularization has been obtained.
§3. For a religious to transfer from an autonomous monastery to another of the same institute or federation or confederation, the consent of the major superior of each monastery and of the chapter of the receiving monastery is required and is sufficient, without prejudice to other requirements established by proper law; a new profession is not required.
§4. Proper law is to determine the time and manner of the probation which must precede the profession of a member in the new institute.
§5. For a transfer to be made to a secular institute or a society of apostolic life or from them to a religious institute, permission of the Holy See is required, whose mandates must be observed.
Source: Code of Canon Law (Vatican.va)