DEAR MISS MANNERS: I am in a pickle. Every year, my family hosts a formal, multiple-course Christmas dinner for our closest friends. We are limited to nine couples at the table. We usually have more friends than we have seats. We request RSVPs early so we can invite other couples in case somebody cannot make it. This year, we invited two new couples to the party (having to remove two couples who attended prior), and one of them replied that just one person is attending because her significant other won’t be around. What do I do now? Go on with the party even though she will be the only “solo” …