The Raven Queen warlock patron (from Unearthed Arcana: Warlock & Wizard) grants the Sentinel Raven feature at 1st level, part of which says:
While perched on your shoulder, the raven can’t be targeted by any attack or other harmful effect; only you can cast spells on it; it can’t take damage; and it is incapacitated.
In combat, you roll initiative for the raven and control how it acts. If it is slain by a creature, you gain advantage on all attack rolls against the killer for the next 24 hours.
Can you have the Sentinel Raven start out perched on your shoulder and then, on its turn, have it lift off your shoulder, use the Help action to give you advantage on an attack, and then perch on your shoulder again? This would make it unable to be targeted or damaged, but still give you (the warlock) advantage on your next attack.
Am I correctly interpreting the rules here? Is it possible to have the Sentinel Raven start perched so it can't be harmed, Help on its turn, and perch again at the end of its turn?