You can only change ONE letter, AND/OR rearrange the letters currently available. The first word is:
WINS
mole
sole
less
lens
sent
neat
peat
pest
stop
poet
pout
tour
rotor
Oh, Christine, I'll send the rotor on a diet to shrink it into a 4 Letter Word again :)
root
moot
room
boom
mobs
I knew something was wrong but I didn't see what
boms
bomb
boob
noob
[slang]
bone
lone