My child's baby tooth just refuses to drop even though all the other teeth have changed, what should I do??

How old is your child? I think delayed tooth loss is nothing to be too worried about. My niece, who's 8 now, took some time to lose her baby teeth but she did so eventually at the age of 6. It really varies for different children. Such inactivity is unexpected by parents but completely normal. Most dentist will not worry about delayed tooth loss unless they find the following complications: 1) the retained primary teeth are causing problems for the incoming permanent ones 2) the molars are already erupted, 3) the delayed tooth loss will cause orthodontic treatment to be started at an awkward age.