To end the pacifier habit you should go about it in small steps. If you reduce the time on the pacifier ever day, you will notice that the transition will go much smoother. Another tick is to keep your child occupied with another activity or toy when they're asking for their pacifier.
Is the absence of a pacifier the cause of increased sadness? In most cases some extra comfort with attention, love and music could do the trick. Changing the pacifier for another toy is a fun adventure for older children. Take your child to the store and let them pick out the perfect alternative for the pacifier. They will love it.
It is normal when your child is sad due to the lack of a pacifier. Laughing away this sadness could feel hurtful to your child. Explain in a calm manner that this is part of growing up and other children are going through the same thing.