CCC 1515 If a sick person who received this anointing recovers his health, he can in the case of another grave illness receive this sacrament again. If during the same illness the person’s condition becomes more serious, the sacrament may be repeated. It is fitting to receive the Anointing of the Sick just prior to a serious operation. The same holds for the elderly whose frailty becomes more pronounced.
CCC 1516 Only priests (bishops and presbyters) are ministers of the Anointing of the Sick.1 It is the duty of pastors to instruct the faithful on the benefits of this sacrament. The faithful should encourage the sick to call for a priest to receive this sacrament. The sick should prepare themselves to receive it with good dispositions, assisted by their pastor and the whole ecclesial community, which is invited to surround the sick in a special way through their prayers and fraternal attention.
1 Cf. Council Of Trent (1551): DS 1697; 1719; CIC, Can. 1003; CCEO, Can. 739 # 1.