If the typo made it into an e-mail or e-mail attachment, you won't be able to get it back. First, make sure it doesn't happen again. If you inadvertently misspell a name, it can help to extend an apology and say it won't happen again. That depends on your comfort level.
"There's no magic answer that's going to fix that with anyone," Johnson said. "You've got to go with our gut."