They obeyed the summons of the conch, partly because Ralph blew it, and he was big enough to be a link with the adult world of authority; and partly because they enjoyed the entertainment of the assemblies.
Ralph summoned his wits.
There are no more uses of "summon" in the book.
Show samples from other sources
I was summoned to the principal’s office.
I summoned all my courage and walked into the room.