When your ally struggles to recall an important fact, you supply a story to nudge him or her onto the right path.

Encounter
Immediate Reaction      Close burst 5

Trigger: An ally within 5 squares of you makes a knowledge check and dislikes the result

Target: The triggering ally in the burst

Effect: The target rerolls the knowledge check and uses either result.

Published in Player's Handbook 3, page(s) 170.