I understand that only certain persons can perform certain acts. A bishop can ordain. A priest can baptise and chrismate.
Deacons may: orthodoxwiki.org/Deacon
The deacon ministers to the priest and bishop in the divine services. This includes:
Assisting in the celebration of the mysteries of the Church
Leading the people in the collective prayers (with the blessing of the presiding priest or bishop)
Reading from the Scriptures during the divine services (with the blessing of the presiding priest or bishop)
Keeping the decorum of the public worship, including calling people to attention at appropriate times
Any tasks of the subdeacon or reader
Other tasks related to Church life, with the blessing and direction of his priest or bishop.
In some jurisdictions, a deacon may be blessed by his bishop and parish priest to distribute the Eucharist to the faithful, either from a second chalice at a regular liturgy where a priest is serving or in connection with a typika service that is celebrated when the priest is absent.
What a deacon does may depend on jurisdiction - some consider the diaconate as a short interval before the priesthood - but, where permanency or longevity in the diaconate is prized, deacons will often head educational programs and youth groups, perform hospital visitation, missionary work, and conduct social welfare projects.