.htaccess to accept parameters in URL

Question

I have a WordPress page with the following structure website.com.au/pre-registration/parameter-value/, where the parameter value was originally a GET parameter, but I was requested to make it part of the URL.

How do I make my .htaccess understand that he must disregard the last part and led the user to website.com.au/pre-registration instead of returning a 404? Ideally, it will still display the whole URL, but load only website.com.au/pre-registration

Tried many possibilities I found on the web, but none worked.

My .htaccess looks like this at the moment:

# BEGIN WordPress
# The directives (lines) between "BEGIN WordPress" and "END WordPress" are
# dynamically generated, and should only be modified via WordPress filters.
# Any changes to the directives between these markers will be overwritten.

<IfModule mod_rewrite.c>
Header set Access-Control-Allow-Origin "*"
Header set Access-Control-Allow-Methods "GET,PUT,POST,DELETE"
Header set Access-Control-Allow-Headers "Content-Type, Authorization"

RewriteEngine On
RewriteRule .* - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization}]
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

# END WordPress

Answer 1

Htaccess wasn't cooperating to the solution, so went for WordPress actions as shown in this answer and added the following to functions.php:

add_action('init', 'prereg_init');
function prereg_init()
{
    // Remember to flush the rules once manually after you added this code!
    add_rewrite_rule(
        // The regex to match the incoming URL
        'pre-registration/([^/]+)/?',
        // The resulting internal URL: `index.php` because we still use WordPress
        // `pagename` because we use this WordPress page
        // `designer_slug` because we assign the first captured regex part to this variable
        'index.php?pagename=pre-registration&clubg=$matches[1]',
        // This is a rather specific URL, so we add it to the top of the list
        // Otherwise, the "catch-all" rules at the bottom (for pages and attachments) will "win"
        'top'
    );
}

Worked like a charm.