Hi @Muhammad Ammad Shah ,
>When I try to change the database instance from desktop edition to standard edition I am unable to view the instance while browsing SQL.
Is this a named instance or default instance? Did you try to using SSMS to connect to the SQL server 2012 standard edition? Using SSMS 18.8, you can get it from here. In the Server name box, type the name of the instance of the Database Engine. For the default instance of SQL Server, the server name is the computer name. For a named instance of SQL Server, the server name is the <computer_name>\<instance_name>.
Please check the ‘Hide Instance ‘option as Erland mentioned, set the Value of this to NO.
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