A HelloGoobyeTopic is used for both greeting and farewell. It may be difficult to imagine how the same response could be suitable for both, but perhaps the following (which we'll use for the curator - put it in his ConversationReadyState) just about does the trick:
+++ HelloGoodbyeTopic
"<q>Good day!</q> you greet him.\b
<q>Good day to you,</q> {the curator/he} replies. "
;