It depends on what you currently have. I was National Exec already and a few weeks ago did a status match to Hertz presidents club. National requested additional documents. I provided a screenshot of the welcome email from hertz and a copy of my hertz card (from hertz website). It took 3-4 days for them to approve it.
Once approved it was suppose to take up to 7 days for your national account to be updated. Mine wasn't updated after 7 days so I opened a support ticket via the website. It took multiple emails and another 10 days for them to get it updated. They had to manually update it. I think its because I was already Exec. In the research I found online it seemed like years ago National's system may have issues with status matches going from Exec to Exec Elite.