While Elise went to save her aunt and bring her back, Weiss was participating in the grand party alone. This was actually not a problem for her and she was doing fine.
The main help that Elise gave Weiss in this party was to handle the vast amount of people greeting her at the start of the party. But that rush was already over, so Weiss had nothing to worry about.
There were a few nobles who were curious about why Elise needed to suddenly leave in the middle of the party. But after learning from their men that she had directly entered her room and had not came out ever since, they had came to the conclusion that she was feeling ill for one reason or another.
Even though official knights were way too sturdy, it was not like they were invincible or free from all kind of sickness. There were even life force related special illnesses that only an official knight could show symptoms of.
