You currently use Outlook Express and your business now has an Exchange box. You want to stop accessing the new box via POP3 and start accessing it as an Exchange server.
You should already configure Outlook to Exchange before completing these steps.
You can export your .PST and import the .PST in Outlook as a new LOCAL .PST file, but that is not having Exchange-based mail.
If you have both installed on the workstation you can migrate from "local storage" to your "Exchange mailbox".
1. Start Microsoft Outlook Express.
2. From the File menu, choose the "Export" option.
3. Select a "profile" for your (full) Outlook Exchange client.
4. Select the individual folders you what to export, or click All Folders to migrate everything.
5. Wait why the export processes