The phone line can also ‘offload’ you too and mark you for a refund of any tax (as you didn’t travel) or a refund if fare rules allow. IME they will be flexible about this - ie if you genuinely can’t travel they won’t tend to say you checked in, passed thru security & used the lounge so no refund etc.

The escorts used to (I’m talking 2014 when I needed to abort a trip) go from the airside customer service desks, I forget if they call it north or south, but basically the ones with “flight management” on the screen. I think it was to do with being a domestic.