Keep my email on my iPhone after delete them from server

Hi

I have problem with my company email, so I changed the company that host my company website, On my iPhone I have all the old messages from my emails

(myemail@mycompany.com), after change the hosting company I have the same email address (myemail@mycompany.com) BUT it's new email with empty inbox,

If I connect my iPhone I will lose all email,

How can I keep the old messages in my iPhone ?

Hope that clear

Thanks in advance

Abdusalam