When someone shoots at you or swings a vibro-ax, you can try to get out of the way—that's where reaction skills come in. (As explained in "The Rules," you can use a reaction skill at any time.)
Dodge: avoid ranged attacks (blasters, bullets, missiles, grenades). If you don't have dodge, use Dexterity. Melee parry: defend against brawling or melee weapon attacks while holding a melee weapon (knife, vibro-ax, chair, mug, etc.). If you don't have melee parry, use Dexterity. If defending against an unarmed attacker with no sharp natural weapons: +5 to melee parry roll. Brawling parry: defend while unarmed. If you don't have brawling parry, use Dexterity. If defending unarmed against a weapon or sharp natural tools: attacker gets +10 to attack roll. Lightsaber: if wielding a lightsaber, use the lightsaber skill (or Dexterity) to defend. Vehicle dodge: if piloting/driving a vehicle, roll its operation skill (often repulsorlift operation, or Mechanical if not trained). Vehicle combat is covered in "Movement and Chases." Starship dodge: if piloting a starship, roll capital ship piloting, space transports, or starfighter piloting (Mechanical skills). Starship combat is covered in "Space Travel and Combat."
When using a reaction skill, the defender makes the roll (apply multiple-action penalties). The result becomes the attacker's new difficulty number for all attacks of that type against the defender for the rest of the round.
Combat in the Star Wars game is fairly lethal. The key to survival is not getting hit. If someone is shooting at your character, consider dodging. If someone attacks with a vibro-ax or lightsaber, consider parrying.
Just like in the movies, most characters who get shot are seriously injured or killed. You've been warned!
Note: A poor reaction skill can actually make it easier to hit a character—sometimes people leap into the line of fire or move into an attack.
A stormtrooper shoots at Thannik at short range: Easy difficulty, difficulty number 8. Thannik dodges and rolls 27. Now the stormtrooper must roll 27+ to hit Thannik. Anyone else who shoots at Thannik this round must also roll 27+. However, if someone makes a brawling attack on Thannik, the difficulty is still Very Easy (difficulty number 5) unless Thannik also brawling parries. One round later, three stormtroopers shoot at Thannik. Their original difficulties are 6, 8, and 17. Thannik dodges and rolls 14—now all three troopers must roll 14+ to hit him.
A character can make a full reaction (dodge, melee parry, brawling parry, lightsaber, vehicle dodge, or starship dodge). A full reaction must be the character's only action in the round. The character rolls the reaction skill and adds it to the difficulties of all attacks made against them that round.
Example: Thannik is shot at by three stormtroopers: two at medium range (difficulty number 13) and one at short range (difficulty number 8). Thannik makes a full dodge and rolls 27. Medium-range troopers must roll 40 (13 + 27) Short-range trooper must roll 35 (8 + 27)
Later that round, a thug attacks Thannik with a vibro-ax (melee attack, difficulty number 12). Thannik can't melee parry because he used a full dodge; he has to hope the thug misses.
Source: REUP