Because the other card must be in my older sister's name but it was mistakenly reserved in my own name. So I contacted the owner of the event and he was informed and gave permission to change the name to my sister's name.
Because the other ticket must be in the name of my sister, but the reservation was incorrect. He went to see his master and asked him to change his name to his sister's.
Because the other card must be her sister's name, but she booked her own name by mistake, she greeted the owner and he was allowed to change her name to her sister's name.