Be careful, Tim.  What immediately came to my mind was that you should not replace your with yor.  Probably many others also should not be converted.  I do not have the real answer, but suspect it should conform to “replace specficword[our] with specificword[or]” using a list of words known to vary in that way.  Safest might be to create a list of all words in your document which end in our, then manually cull the list the specificword list.  Hmm, “our” is another which you should not replace with “or”.  

Sorry for providing only a restatement of the problem.  My recent use of NWP has been mostly read-only, so I don’t have easy use of NWP’s text conversion capabilities.  I do remember getting bitten by using its power without adequate care.

Tom

> On Jun 15, 2015, at 7:12 AM, Timothy Williams <[log in to unmask]> wrote:
> 
> People
> 
> 
> The good news is the publisher has accepted a book for publication. The bad news is I must Americanise - sorry, Americanize - the spelling.
> 
> How do I find a word ending in -our and replace it with -or?
> 
> TIA
> 
> 
> T