Because I found myself in need of a generic greeting:
Ashaltiasten
Ashal - good, blessed, holy
tiast - time, moment
-en - plural suffix
Basically a broad "good morning/day/evening" that could either be an organic development or something that came out of post-unification Athran society where people were communicating across timezones, and which carried over into space as people were operating on completely different local clocks.
As I resent the shortening of this greeting to "Ashal" (it's just sloppy language ;P ), but acknowledge the fact that it gets quite repetitive if the proper response is Ashaltiasten as well, I put a little thought into that.
My suggestion is that the proper response would be something along the lines of "Ashalagram":
Ashal - truth, holiness, right, good
agram - endless, eternal (cf. herartagram - endless night)
So, the response would be an affirming "Good(ness) eternal!" What do you people think? Horatius?