Merge query or cfset data with word docx or doc and download the updated version

I have a word docx named coded_word.doc that is coded (written)  like this

%COURTESY_TITLE% %FIRST_NAME% , %LAST_NAME%

Dear %COURTESY_TITLE% %LAST_NAME%,

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I have cf code like this

<!---Read the file--->

<cfset mydoc= FileRead("#GetDirectoryFromPath(GetCurrentTemplatePath())#coded_word.docx") />

<!---Replace the coded variables in he word doc withthese values. These ultimately will be from a query result--->

<cfset mydoc= Replace(rtf,"%COURTESY_TITLE%","Mr.") />

<cfset mydoc= Replace(rtf,"%FIRST_NAME%","Charles") />

<cfset mydoc= Replace(rtf,"%LAST_NAME%","Jones") />

<!---Then download the modified file--->

<CFHEADER NAME="content-disposition" VALUE="attachment; filename=mydoc_updated.doc">

<cfcontent type="application/vnd.ms-word" file="#GetDirectoryFromPath(GetCurrentTemplatePath())#mydoc_updated.doc">

But when I do I get the original word doc. I don't get  mydoc_updated.doc.

I want to merge/replace the %variable% with actual/set values and need the updated version mydoc.doc to download like this

Mr. Charles Jones

Dear Mr. Jones

QUESTIONS

1. Do I have the coding correct in the word doc?
2. Do I need to save and rename the new file before downloading?
3. Can I use .docx extension or does that create additional issues as I probably can't use <cfcontent type="application/vnd.ms-word" ?
4. I need the original coded_word.doc to stay the same as it is a template that I'll need for the next query result.