Got this from the football manual on the NSAA web site.
Page 31
If schools mutually agree to cancel a game after August 24 it will count as a loss for both teams.
Page 33
If two schools cannot agree on the postponement of a regular season football game and the schools contact the NSAA office for a ruling, first priority shall be given to player safety. The host team has the sole responsibility of determining if the field is fit for play. The game may be postponed or forfeited. If a forfeit is not awarded, the game must be completed by 12 noon on Saturday of the school’s last permitted regular season game. If the game is not forfeited and is not played by the stipulated date, each team will be credited with a loss