Handbook of ROCOR Liturgical Practice:

Who may commune at the Presanctified Liturgy, and how are the Holy Gifts to be offered to them?

The expectations for preparing to receive Holy Communion at the Divine Liturgy of the Presanctified Gifts are the same as for receiving the Holy Mysteries at any other Liturgy. The communicant should prepare by repentance and confession, communing with the blessing of the Priest; and should keep the Eucharistic fast prior to receiving the Lord’s Body and Blood. When the Presanctified Liturgy is celebrated in the morning, the individual should fast from the night before (i.e. from going to sleep, and should neither eat nor drink anything on waking, prior to receiving Holy Communion, just as on a Sunday); when the Presanctified is celebrated in the evening, the highest ideal is to keep a strict fast the whole day, from the moment of rising from sleep — however, if the practical needs of living in the world make this impossible, the individual intending to commune in the evening may have a little to eat in the morning, but must fast strictly from at least midday in order to prepare his or her heart for the Divine Gifts.

At the time of the communion of the faithful, the Priest administers the Holy Gifts to the faithful in precisely the same manner, and with the same words, as at the Divine Liturgies of Sts John and Basil.

Infants: Small children may commune at the Presanctified Liturgy if they are able to receive the solid food of the Lord’s Body that has been intincted with His Blood, as it is offered from the chalice. We do not commune babes-in-arms or small infants at the Presanctified Liturgy as we might at the Liturgy of St John (i.e. from the Blood alone). Explanation: We do not present babes-in-arms to receive Communion at this service if they are unable to receive solid foods, since the Blood of Christ is offered in the Presantified Liturgy intincted into the Body and are received together. Lest any think that this in some way ‘deprives’ the littlest ones from this service, let us remember this: the Divine Liturgy of the Presanctified Gifts is offered on weekdays in the Great Fast as a condescension to those whose infirmities are magnified by the strictness of our fasting, and thus require the additional strength in order to make it through the week to the festal celebration of the Eucharist on the weekends of Lent. As babes and infants are not expected to fast in this way, this divine condescension to the infirmities of ascetical endeavour does not apply to them.