Migrating Desktop Central refers to moving the existing installation from one computer to another without losing the data and configuration. There may be many situations where you would need to migrate, like:
You have been evaluating the product in some test computer and you would like to move this to a dedicated computer or server after you have decided to purchase it.
The disk space is running low and you wish to move this to a different computer.
You are upgrading the hardware.
Refer migration document for detailed steps on migrating a Desktop Central server installation from one computer to another without losing any data.