Lisa's Persian cat went missing, and she placed an advertisement in Sabah Daily newspaper offering a reward of RM500 to anyone who can find her missing cat and return it to her. Zack, Lisa's neighbour, heard from Bobby, Lisa's son about the reward. Zack later found the cat near the drain next to his house and picked it up. When he returned the cat to Lisa, she was delighted but said nothing about the reward. The following day, Zack read the advertisement in the newspaper about the reward. Zack then made inquiries about the reward. Lisa now refused to pay the reward, saying that she changed her mind about paying the reward. Advise Zack.