Should the pharmacist pay the employer for the slight shortage resulting from the unavailability of change for customers, in order to avoid sin?

If people leave a small amount of money with you because they disdain it, you are not obliged to give it to the shop owner; rather, it is better to spend it on charitable causes. However, if you are the one who leaves a small amount of money due to a lack of change, there is usually no blame on you, as people are lenient in such matters, but it is better to inform the shop owner.