An Oath of Ancients Paladin may use her Channel Divinity class feature to apply Nature's Wrath:
Nature's Wrath: As an action, you can cause spectral vines to spring up and reach for a creature within 10 feet of you that you can see. The creature must succeed on a Strength or Dexterity saving throw (its choice) or be restrained. While restrained by the vines, the creature repeats the saving throw at the end of each of its turns. On a success, it frees itself and the vines vanish.
If a creature fails the initial save and becomes restrained, can it use its action to attempt to free itself on subsequent turns (similar to how a grappled creature can use its action to attempt to escape the grapple)?
Or is it only allowed to escape by passing the save at the end of its turn(s)?