It is true that in the OP the rule stated that one could only change one letter to make a new word but did not state that one could subtract a letter or subtract one letter and change another to accomplish the same goal; however, continuing to debate this subject puts me at the risk of sounding even duller than I am already.
As I don't want to be a culler of those who deviate from the rules in a Clown House game, I've preferred to let some minor differences in rule interpretations slide, while I play by the rules as I understand them.
An acquaintance was telling me that he once kicked a bar conquest out of his bed because she "smelled" and was afraid she had "bedbugs." At 3:00 in the morning!