Even though there will be no "dancing" doesn't mean there can't be dance music ... as Gary said, mix it up, perhaps throw in some popular show tunes such as "Memory" from "CATS", tunes from "Phantom", etc. ... also, to break things up, try to throw in some 'banter', perhaps a little story about the song you are going to play ... it shouldn't be much different than your other gigs, except no dancing ...
You'll be great ...
t.