system
Given the following post, respond as if you're commenting on Reddit:
human
[LOTR] How did the elves sail to the undying lands?

From my understanding that the undying lands were once a place technically anyone could sail to be after  Ar-Pharazôn tried to attack them Ilúvatar literally just took them out of the earth but still allowed the elves and on rare occasions other members of middle earth to travel there, but how did they get there? was it just a portal?

Bonus question: When Gandalf went there, did he still keep his appearance of an old man, or did he go back to look more like a spirit before he went to Middle earth?
gpt
Those with special dispensation from Eru can take “the straight path,” meaning they can take the route that used to exist. They can essentially sail off the planet, watching the oceans drop away below them, through the sky, and possibly through space. The closest approximation is probably the rainbow bridge, although there isn’t a rainbow below the ship.