§1. Within the scope of universal law, it belongs to proper law to determine acts which exceed the limit and manner of ordinary administration and to establish what is necessary to place an act of extraordinary administration validly.
§2. In addition to superiors, the officials who are designated for this in proper law also validly incur expenses and perform juridic acts of ordinary administration within the limits of their function.
§3. For the validity of alienation and of any other affair in which the patrimonial condition of a juridic person can worsen, the written permission of the competent superior with the consent of the council is required. Nevertheless, if it concerns an affair which exceeds the amount defined by the Holy See for each region, or things given to the Church by vow, or things precious for artistic or historical reasons, the permission of the Holy See itself is also required.
§4. For the autonomous monasteries mentioned in can. 615 and for institutes of diocesan right, it is also necessary to have the written consent of the local ordinary.
Source: Code of Canon Law (Vatican.va)