Use https://secure.logmein.com/home to get to remote LogMeIn access.
1. As admin on the pbx go to Devices and select first device. Go to Lines & Buttons tab and delete existing Line. Add new line but don't resynch yet. Don't forget to Save.
2. Go to Devices and select second device. As above, delete existing line and Add new line. Don't forget to Save.
3. In the General tab for each device, verify the Name and Assigned User. Don't forget to Save.
4. Now resynch, either from PBX or power or phone.
May need to delete and recreate user profiles after switching to let software 'forget' about prior line mappings.