Remove On-Prem Exchange Mailbox from iPhone
- Go to Settings -> Mail -> Accounts
- Select the City email account, then select “Delete Account”
Add Exchange Online (O365) Mailbox to iPhone
- Go to Settings -> Mail -> Accounts – > Add Account
- Select Microsoft Exchange
- Enter your City email address and select Next
- Select Sign In
- You’ll be redirected to the sign on page shown here. Enter your City email and password and select Sign In
- Finally, select the items you wish to sync and select Save
