Rename logical and physical names of database files in SQL Server | SQL Server Administration Blog | zarez.net

To rename the Logical names of database files:

ALTER DATABASE [Database_name] MODIFY FILE (NAME=N'Logical_file_name', NEWNAME=N'Logical_file_name_new')
GO
ALTER DATABASE [Database_name] MODIFY FILE (NAME=N'Logical_file_name_log', NEWNAME=N'Logical_file_name_log_new')
GO