I believe the word you're looking for is, ahem, chode. Although it's usually spelled "choad."
CLOSE
CLONE
CRONE
CRANE
CRAZE
GRAZE
GRAPE
GRIPE
TRIPE
TRIBE
BRIBE
BRIDE
PRIDE
PRUDE
PRUNE
PRONE
DRONE
DROVE
GROVE
GRAVE
CRAVE
CRATE
GRATE
Man, that sucked. The R and the E hardly ever changed.