If you installed a full edition (e.g. standard or enterprise edition) in a lab environment and you need to migrate to developer edition - these are the steps to follow.
Create a Full backup of all user and system databases. Ensure that the backup completes successfully before continuing.
Note your current SQL Server minor version, service pack, cumulative updates, and the General Distribution Release (GDR). For more information, see Determine which version and edition of SQL Server Database Engine is running in the Microsoft documentation.
Detach all user databases.
Stop the SQL Server Database Engine service and copy the log and system database data files—master, model, and msdb—to a local backup folder.
Uninstall SQL Server Enterprise edition including all components.
Reboot the instance.
Install SQL Server Standard or Developer edition according to your requirement.
Install the same service packs and cumulative updates that you had before the uninstall.
Stop the SQL Server Database Engine service.
Using the backups you made in step 4, restore the master, model, and msdb databases.
Start SQL Server service.
Attach the mdf and ldf user databases that were detached in step 3 to your SQL Server instance.
Confirm that your database is operating as expected.