Unable to change Agent Operators
On a case insensitive server, those two names are identical. I am not sure if you are using the UI for this, but I get the same error when I run the following code:

USE msdb;
GO
EXEC dbo.sp_add_operator @name = N'NIT and Arts';
GO
EXEC dbo.sp_update_operator @name = N'NIT and Arts', @new_name = N'NIT and ARTS';


Yields:


  Msg 14261, Level 16, State 1, Procedure sp_verify_operator, Line 38
  The specified @name ('NIT and ARTS') already exists.


If we look at the code for sp_verify_operator, we see that there is a weakness here as a penalty for not using a surrogate key: it checks all existing rows for a match on name, including the row you are trying to change:

  -- The name must be unique  
  IF (EXISTS (SELECT *  
              FROM msdb.dbo.sysoperators  
              WHERE (name = @name)))  
  BEGIN  
    RAISERROR(14261, 16, 1, '@name', @name)  


Ideally, it should ignore the row you are trying to change, but it can't because there is no way to filter except by the name. And in a case sensitive collation, the above check fails because that row already has that name.

How do we work around this? Well you could rebuild msdb or something in a case sensitive or binary collation, but I think this is easier, just run this query manually:

UPDATE msdb.dbo.sysoperators 
  SET name = N'NIT and ARTS'
  WHERE name = N'NIT and Arts';