As per subject, I was referring to those email addresses that remains in the cache. E.g. Email addresses that were sent/received before. Could it be exported to a file and use it on email client like Microsoft Outlook for e.g.?
Or could it be transferrable to another email account within the same domain; for e.g. from a1@abc.com to a2@abc.com?

Look forward to any suggestions.

Thanks in advance. cheers all.