Page 318 - Bob Holtzman "The Field Guide to Knots How to Identify, Tie, and Untie Over 80 Essential Knots for Outdoor Pursuits"

5. To tighten, pull the standing part against the leg of the loop closer to the working end.

Untying: Pull up on the bight that goes around the standing part to free the
working end from the crossing turn.

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