In Interstellar Operations: Battleforce, pag. 177, we read "If an engagement occurs, both Squadrons will maneuver for advantage. If the defending Squadron in an air-to-air attack has not yet declared its own attack, it may decide whether it will return the attack, attempt to move through the zone, or save its action for an attack against a different target (such as an air-to-ground attack if the engagement occurs in the Central Zone). If the defender chooses not to return the attack when an engagement is initiated, it cannot choose to engage its attacker later in the same turn."
This paragraph is riddled with things that are not clear, at least for me. First of all, why we are talking about a "defending squadron"? In SBF battles there is not an attacker and a defender, there is just a fight where the two formations manouver to have the upper hand! And what it means "If has not yet declared its own attack, it may decide whether it will return the attack, attempt to move through the zone" ... attempt to move? But the combat phase happens AFTER the movement phase! How can a squadron decide to not attack AND move??
About instead the "save its action" I just suppose it means that if a squadron is fighting with more than one enemy engaged formations, it can choose not to attack during a fight instead keeping its to-hit roll for another target, and that choice cannot be rethought later. But that's the only thing that I find clear!