Admin Panel - edit external user names and email addresses
We can't edit external user names once they've been created. If you find the user and click edit, you have no access to change their name or email address. In the case where the email address is correct, but the user name needs to be changed (a misspelling for instance), you would think you could simply delete the user and re-add them - but no. It remembers that email address and automatically fills in the user's name (misspelling and all).
I think it's reasonable to expect you may need to edit a person's name or email address - especially if you haven't even actually invited them yet.