It depends on the status of the email. These are the possibilities:
Infomail, Spam, Virus
If the customer uses archiving, these kinds of emails can be redelivered. Status will stay as delivered. The email will be delivered again, and a new entry will show up in the Email Live Tracking. This new entry will have the reason Statusmail. For customers without archiving it's not possible to redeliver and already delivered message.
These emails cannot be released nor redelivered, because they were rejected either from us or from the destination server, and the sender received a bounce message.