That is because there are open transactions. If those transactions can be killed, then this can easily be done with this SQL
ALTER DATABASE ip_ent_site
SET SINGLE_USER WITH ROLLBACK IMMEDIATE
GO
sp_rename 'ip_ent_site', 'new_db_name' ,'DATABASE';
GO
ALTER DATABASE new_db_name
SET MULTI_USER
GO
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…