Canon 684. §1 Perpetually professed members cannot transfer from their own religious institute to another, except by permission of the supreme Moderators of both institutes, given with the consent of their respective councils.

§2 On completion of a probationary period of at least three years, the member can be admitted to perpetual profession in the new institute. A member who refuses to make this profession, or is not admitted to do so by the competent Superiors, is to return to the original institute, unless an indult of secularisation has been obtained.

§3 For a religious to transfer from one autonomous monastery to another monastery of the same institute, federation or confederation, the consent of the major Superior of both monasteries and of the chapter of the receiving monastery is required and is sufficient, unless the institute’s own law has established further conditions. A new profession is not required.
[NB see Authentic Interpretation of canon 684 §3, 20.VI.1987]

§4 The institute’s own law is to determine the time and manner of the probation which must precede the member’s profession in the new institute.

§5 To transfer to a secular institute or to a society of apostolic life, or to transfer from these to a religious institute, the permission of the Holy See is required and its instructions are to be followed.