Kindly follow the below steps to migrate the SQL DB,
1. Take a backup of "customer-config.xml" file from the location "ManageEngine\OpManager\conf".
2. Take a SQL backup of OpManagerDB from the old server via SQL Management Studio.
3. Create a new DB named OpManagerDB with the same permissions on the new MSSQL databaseserver.
4. Restore the SQL Backup on the new server via SQL Management Studio.
5. Open command prompt as Administrator (right click CMD -> Run As Adminstrator) in the application installed server and go to the path "ManageEngine\OpManager\bin"
6. Execute the command "DBConfiguration.bat" and point the OpManager with the new DB details.
7. Once configured, Replace the existing "customer-config.xml" file from the location "ManageEngine\OpManager\conf" with the backup "customer_config.xml" file that we have taken.
8. Start the OpManager service and check if everything works fine.