I think (but this is the blind leading the myopic) that the original word is an old black and white tv show starring james garner and the replacement is a word for cloth - so you change letters 3,7 and 8. Pretty sure I have the second word of 14 but stuck on the first and have no clue (!) about 3,4,6,8,15 or 21 - so far I have only 5 changers so most of those presumably need to adapt