I have a lot of social aquainatnces who I don't know well, but well enough to have brief conversations with. Somtimes they'll say they can't make a social occasion - not for any sad reason - a few of us are going to. When this happens i find myself rather stuck for what to say.
'No problem'; 'Maybe next time' - I fnd myself churning out the same couple of comments and I'm starting to bore myself!
What could I say that would seem more interesting?