How should a high-ranking officer respond to a salute?

The superior officer is supposed to return the salute. That is standard protocol.

In Canada, you salute the holder of the Queen's fee. I think of it is comparable for the US - officers carry a "fee," that's what you're saluting. The branch would not count - officers get salutes however the branch - and nationality for that count.

They return the salute. The only time they probably won't salute back is if...their hands are both full carrying something else, in that case they'll simply nod their head acknowledging the salute. Also, if they're sitting down, they'll probably just acknowledge it with a nod or tell them to stand at ease.

Wow why would they say Hi?

They don't ignore them they probably do a move that they were thought in bootcamp. They wouldn't say hi because they don't think their civilians (and their not)

Like clap heals and put arms more stuff idk watch some YouTube clips about it and you'll see.

Not trying to be rude I promise. :)

In the British forces an officer (no matter what rank) returns a salute given to him or her. The salute is a recognition that the individual holds the Queen's commission and is, indirectly, a salute of the sovreign. the salute is returned as a recognition of that fact. As others have said, the only time an officer (or anyone for that matter) does not salute is if they are not wearing uniform headress, carrying objects which required both hands, riding a bicycle or driving a motor vehicle. High ranking officers (I.e. those of general rank or equivalent) are saluted by all officers junior to them and by all non-commissioned ranks.

Salute back. Duh!

They don't say hi (come on, really?) nor do they ignore it. They return the salute. The lower-ranking officer needs to hold his salute until the higher rank salutes him.

All Officers acknowledge salutes. In the British forces it is not them that is being saluted , it's the Queens commission that is being saluted.

A non Officer wearing a Victoria cross (Britain's highest medal) is uniquely saluted by a commissioned officer first.

If a soldier in uniform recognises an Officer in civilian clothes he is expected to salute him, and will ordinarily be thanked by the officer who will not have to salute in return, Same thing if an officer is,say at a desk, and not wearing a hat he will not return salute.

A uniformed officer walks into a barrack room soldiers/s will stand to attention but without hats on don't salute, they are still saluted because the act of standing to attention is a substitute.