Once you complete the final operation mission (i.e. Operation: Damocles), you'll return to the city of Seoul. From there click the
button, select missions, then mission replay. Here you can select every operation and mission in the game. Select (3) that you want to replay and enjoy.
Note: This can only be accessed this way. Cannot be accessed via the mission select menu in ARK 1.
Also, as
laws points out you can do the same mission (3) times if you'd like.