Part of the contacts in my iphone are on an an exchange account. How can I eliminate the exchange account with out loosing the data

Please use a web browser to transfer the data from Exchange account to another email account.

1. Try to export the contacts from google mail on a web browser. During Export select export as vCard and then log in to https://www.icloud.com using your Apple ID credentials Tap Contacts app > Settings > Import vCard.
2. You may use this --> Share contacts as vCards - Microsoft Support or Export multiple Contacts as vCards - MSOutlook.info and then log in to https://www.icloud.com using your Apple ID credentials Tap Contacts app > Settings > Import vCard.

You can't.