Book of Common Prayer (page 18)

and Holy Days, the following may be observed with the Collects, Psalms,
and Lessons duly authorized by this Church:

Commemorations listed in the Calendar

Other Commemorations, using the Common of Saints

The Ember Days, traditionally observed on the Wednesdays, Fridays, and
Saturdays after the First Sunday in Lent, the Day of Pentecost, Holy
Cross Day, and December 13.

The Rogation Days, traditionally observed on Monday, Tuesday, and
Wednesday before Ascension Day

Various Occasions

Provided, that there is no celebration of the Eucharist for any such
occasion on Ash Wednesday, Maundy Thursday, Good Friday, and Holy
Saturday; and provided further, that none of the Propers appointed for
Various Occasions is used as a substitute for, or as an addition to, the
Proper appointed for the Principal Feasts.