I made some changes to one page on my website today, so I went through the procedure to re-index just the one page.
From the admin page, I clicked on the website link, then Update Form. From there I clicked on the right arrow to get a list of files that are indexed for that site. I found the file I wanted to update, and clicked the green check mark beside it, which should just re-index that one page. The spider is currently crawling the whole site, not just the one page!