The rules say that all the words in this game must be four letters, so I've done from "twos" to "ones".

Twos
Twas (cheating slightly, as it's a contraction, as in "'Twas the night before Christmas")
Teas
Seas
Sees
Seed
Sped
Aped
Apes
Aces
Ices
Ides
Odes
Ones

Change "pest" to "diva".

(It had been so long that I forgot that most important rule. )

Pest
Lest
Lost
Lose
Love
Dove
Dive
Diva

Change "Four" to "Nine"

Four
Foul
Fool
Pool
Poll
Pill
Pile
Pine
Nine

Change "tree" to "five".

Tree
Free
Flee
Fled
Feed
Fend
Find
Fine
Five

Change "cold" to "ruby".

Cold
Bold
Bald
Bale
Pale
Pule
Rule
Rube
Ruby

Change "scan" to "find".

Scan
Scam
Slam
Clam
Clap
Clop
Coop
c**n
Corn
Cord
Cort
Fort
Font
Fond
Find

Change "Brat" to "Tare"

Brat
Boat
Bolt
Bole
Bore
Bare
Tare

Change "jump" to "east".

Jump
Bump
Bums
Buns
Bunt
Bent
Best
Bast
East

Change "ours" to "your".

Ours
Oars
Oats
Pats
Pate
Pare
Pore
Port
Pout
Pour
Your

Change "acid" to "tops".

Acid
Arid
Grid
Grit
Gait
Bait
Bail
Mail
Mall
Malt
Matt
Mats
Maps
Mops
Tops

Change "bray" to "bark".

Bray
Bran
Bean
Beak
Beck
Back
Bark

Change "yard" to "dray".

Yard
Bard
Bare
Tare
Pare
Part
Pert
Pest
Best
Beat
Brat
Drat
Dray

Change "such" to "char".

Such
Suck
Sock
Soak
Soap
Slap
Clap
Chap
Char

Change "ride" to "boot".

Ride
Rise
Rose
Pose
Post
Lost
Loot
Boot

Change "Jail" to "Lock"

Jail
Pail
Pall
Pale
Pace
Lace
Lack
Lock

Change "crab" to "bark".