Any House Officer may substitute up to two (2) alternative days of their choice for any of the previously defined House Officer holidays within any twelve (12) month appointment period so long as the substitution request is made at least thirty (30) calendar days prior to the House Officer defined holiday selected for substitution or the day selected as the substitute, whichever is closer. Once a House Officer defined holiday has passed, it is no longer eligible for substitution. These substitutions will be mutually agreeable to the House Officer and their Program Director. That House Officer will be eligible for holiday pay if they have any assigned responsibilities by their training program on those agreed-upon substitute dates.