Page 543 - Bob Holtzman "The Field Guide to Knots How to Identify, Tie, and Untie Over 80 Essential Knots for Outdoor Pursuits"

4. Pull the working end tight, then pull the standing part to tighten the knot.

Untying: If the hitch is too tight to pull the working end free, pull slack

from the standing part through the bight, then loosen the bight and the
crossing turn that secures the working end.

539