1. Browse to C:\Users\Username\AppData\Local\Microsoft\Outlook\RoamCache
2. Identify the Stream_Autocomplete file to want to move (Usually largest file and recently used)
3. Make a duplicate of the file.
4. Open new Office 365 profile and send a test email and then restart Outlook. This will then create a new Stream_Autocomplete file.
5. Find the new AutoComplete file, copy the file name and mark current file as "filename".old. Then, paste the file name onto the AutoComplete file you want to migrate to the new profile.
6. Restart Outlook and it will now look at the new file. with all AutoComplete address accessible.