This conundrum has me quite perplexed.
When calling on the youngest daughter of an Earl (The Earl of Broughton-Houghton, if you must know), I was informed that Miss Hardesty-Frumpton was not at home.
I left my calling card with the butler but later realised to my horror that I had inadvertently dropped my mooncup in the hall.
I have consulted Debretts, but this situation does not seem to have been covered.
What should I do?