You don't have to remove a babies pacifier while sleeping.
Actually when babies are younger than 1 year old the pacifier can actually help reduce the risk of SIDS during the night.
Many babies can and do safely sleep with pacifiers in their mouths at night and it also keeps them calm.
Just be sure to check the pacifier for any tears or cracks in the nipple before giving the baby the pacifier and as long as the pacifier is in good condition babies can sleep safely with the pacifier.
Some toddlers even sleep with pacifier until age 4 which is also okay if it soothes them and gets them to sleep.