I have a user who's leaving the company soon.

I'd like to keep his email account live, so that we can refer to it if needed. However the user accesses his email on his iPhone, so I assume has copies of emails on the phone.

Is there an easy way that I can clear the email off the phone?

I'm assuming that I could move the emails out of the account somehow, then when IMAP syncs it will clear the inbox. Can someone tell me an easy way to achieve this please?