Can a recommendation be edited after submitting? What is the procedure? Has anyone experienced this?
Does the school your applying to use an electronic submission? Have you formally submitted the entire application yet? If so, it could be hard to change anything.
If you haven't yet formally submitted, you may be able to change it though it still probably depends on the policy of the school you're applying to. I was able to have a recommendation resubmitted at Sloan, which uses an electronic process through ApplyYourself. One of my recommenders submitted early and later decided they wanted to add something to it. I called the admissions office and explained the situation to them, and since it will still before the submission deadline and I hadn't yet submitted the final package, it wasn't a problem. A person at the office manually detached the old recommendation file, which enabled my recommender to upload a new file, and the previous version was never included in my final package.