Who is sent to deliver the message from Zeus to free Odysseus?

Hermes is sent by Zeus to deliver the message to Calypso, instructing her to free Odysseus. This occurs in Homer's "Odyssey," where Zeus orders Hermes to ensure that Odysseus can finally return home to Ithaca after being held captive for many years. Hermes, as the messenger god, plays a vital role in facilitating this important turning point in Odysseus's journey.