Saul disguised himself because the way from Gilboa ([1 Samuel 28:4](../28/04.md)) to Endor ([1 Samuel 28:7](./07.md)) was through land that the Philistines were living in. He traveled all day and reached the woman after the sun had gone down.
Saul was requesting that the woman call on the familiar spirit she used to contact the dead and have that spirit call up the spirit of the dead person Saul would name.