The following is sourced from the statutes of the Eparchy of St. Maron of Brooklyn.
The faithful are bound by the obligation to participate in the Divine Liturgy on Sundays and Holy Days of Obligation.
The available time to fulfill this obligation runs from 4:00 pm on the vigil, until the end of the Sunday or the Holy Day.
The following Holy Days of Obligation are to be observed, and they cannot be suppressed or transferred to a Sunday:
All Saints (November 1)
The Immaculate Conception (December 8)
The Nativity of the Lord (December 25)
The Circumcision of Our Lord (January 1)
The Glorious Epiphany (January 6)
Saint Maron (February 9)
The Ascension of the Lord (40 days after Easter)
The Assumption of Our Lady (August 15)
The Patron of the parish. [In this case, if this feast is not one of the above-mentioned Holy Days, it may be transferred to a Sunday at the pastor’s discretion. - Eparchy of St. Maron of Brooklyn]