Reserves on the operational phase
Part of the troops in an operation are in reserve. In the game, reserves are of two types: forces "pool" to which active platoons are attached, and reserve platoons, which are located at the operational map edge (perimeter). The pool attached to a platoon can be used to replace or reinforce the active platoon. Typically, the forces in the "pool" are support, or captured units, or combat units exceeding the size limits of a platoon. The bulk of them - those that are defined by the organization structure, and the small part - those who theoretically could have been involved in the operation. The second can be disabled in the realism options.
Platoons located at the operational map perimeter become available after a certain turns after the start of operation. The remaining number of turns is displayed next to the commander's name near the platoon icon. Remember, platoons located at the map perimeter cannot attack. They must be moved to neutral or allied squares on the main field before the battle. In turn, you can also block the approach of the enemy reserves using this feature - taking positions on squares near the map perimeter. In some operations extra victory points are awarded for keeping (not deploying) the reserve platoons.