Hello @NichelleE3 ,
You cannot rescind sent emails. Once an email has been sent, it's like a stamped letter being instantly transferred from you putting it into the mailbox to the recipients' mailbox to be opened. Some internal email servers can "rescind" sendouts, however this is simply not possible for ESPs like us since we do not have access to recipients' mailboxes - especially since we do not have access to their email servers, security systems, etc.
If you need to issue a correction, we advise copying the email you sent, making the edits, and changing the subject to something like "Corrected:" or "UPDATE:" and then the rest of the original subject.