Why did Saul seek the help of the necromancer at Endor after Samuel’s death?

Saul sought the help of the necromancer at Endor because he was deeply concerned about the final outcome of Israel’s impending battle against the Philistines.1

Despite having previously banished all sorcerers and conjurers from his kingdom, Saul’s desperation led him to seek someone with a "familiar spirit" to conjure the ghost of the prophet Samuel. Saul hoped to receive a word of encouragement or guidance regarding the war. However, the spirit of Samuel instead foretold the defeat of the Israelite forces and the death of both Saul and his sons in the upcoming battle.123