appear at
To arrive at or be in a particular location at a certain time. My sister's favorite singer is appearing at the mall today. I'm stuck in traffic, so I won't appear at the party for a while.
appear at
some place to perform at a particular place. She is appearing at the Bijou all month. I will appear at Carnegie Hall soon.
appear at some time
to arrive at a particular time. I am due to appear at the council at noon. I will appear at the meeting whenever my plane gets in.