Can. 362 The Roman Pontiff has the innate and independent right to appoint, send, transfer, and recall his own legates either to particular churches in various nations or regions or to states and public authorities. The norms of international law are to be observed in what pertains to the mission and recall of legates appointed to states.
Can. 363 §1. To the legates of the Roman Pontiff is entrusted the office of representing the Roman Pontiff in a stable manner to particular churches or also to the states and public authorities to which they are sent.
8/ in addition, to exercise the faculties and to fulfill other mandates which the Apostolic See entrusts to him.
2/ to deal with questions which pertain to relations between Church and state and in a special way to deal with the drafting and implementation of concordats and other agreements of this type.
2/ after he has notified in advance the local ordinaries insofar as possible, a pontifical legate is permitted to perform liturgical celebrations in all churches of his legation, even in pontificals.
Can. 367 The function of a pontifical legate does not cease when the Apostolic See becomes vacant unless the pontifical letter establishes otherwise; it does cease, however, when the mandate has been fulfilled, when the legate has been notified of recall, or when the Roman Pontiff accepts the legate’s resignation.