Is the money earned by a sales manager from selling goods at a price higher than the specified amount, without the employer's knowledge, permissible?

If a person appoints another to sell an item, the agent is not permitted to profit from it. Rather, any profit or discount generated belongs to the owner of the asset. If the owner specifies a certain price, and the agent sells it for more, the increase belongs to the owner, unless he grants permission for the agent to keep it. The agent is entrusted with the goods and their price, and taking any increase without the owner's knowledge is considered a betrayal of trust and an unlawful appropriation of people's wealth, which is forbidden for him.