Mod Rewrite for Wordpress

I am trying to insert some custom PHP code into a wordpress site. I just created a new template page and added my code there. Thats fine.
My site doesnt use file extensions suffix on file names (

for the sake of my PHP app i need to add php variables, such as

This will trigger certain items in the code I added.

HOW CAN I REDIRECT to name-of-permalink.html JUST FOR THIS PAGE?
I don’t want the.html plugin as my site is indexed with google and SEO is strong. Need to only do this for this one page.

I’m sure its a .htaccess file modification. Just don’t know how because wordpress already has some .htaccess file configuratoins.

Here is whats in it right now.

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d

RewriteRule . /index.php [L]

# END WordPress

#RewriteCond %{HTTP_HOST} !^$
#RewriteRule ^(.*)$$1 [R=301]