The database could not be exclusively locked to perform the operation. (Microsoft SQL Server, Error: 5030)

First we will see how to set the database to single user mode,

ALTER DATABASE dbName
SET SINGLE_USER WITH ROLLBACK IMMEDIATE

Now we will try to rename the database

ALTER DATABASE dbName MODIFY NAME = dbNewName


Finally we will set the database to Multiuser mode


ALTER DATABASE dbNewName
SET MULTI_USER WITH ROLLBACK IMMEDIATE


source :
http://weblogs.asp.net/varadam/archive/2012/08/10/the-database-could-not-be-exclusively-locked-to-perform-the-operation-microsoft-sql-server-error-5030.aspx