Formal:
* A hui hou kākou: This literally translates to "until we meet again, all of us." It's a very common and respectful way to say goodbye.
Informal:
* A hui hou: This is a shorter version of "a hui hou kākou" and is often used between friends.
* E ʻike hou kākou: This means "we'll see each other again."
* Ke kali nei au iā ʻoe: This means "I'm waiting for you." This is more of a "see you soon" type of expression.
More poetic:
* A hui hou ma kahi ʻē aʻe: This means "until we meet again in another place."
The best choice for you will depend on the specific situation.
For example, if you are saying goodbye to a friend, you could use "A hui hou." If you are saying goodbye to a group of people, you could use "A hui hou kākou." If you want to be more poetic, you could use "A hui hou ma kahi ʻē aʻe."