Seven letter words change one or two letter to make a new word

shimmer

merriam

ramming

Teaming

teeming

misting

smidgen

genders

degrees

breezes

freezer

freemen

ferment

Mentos

cements

comment

commode

command

I count 6 letters no matter how I look at it.

Commune

Yeah, we all slip up occasionally.

commute