Using case to delete data row

I created a simple stored procedure to update my table, but currently what I need is

Delete * from [ABCSystem].[dbo].[NEW_TEST_NUMBER] 
WHERE sONbr = @sONbr AND SOLine = @SOLine

If @Statuscode is = "N001" by using case. Anyone can show me a simple sample or something?

Thank you.

ALTER PROCEDURE [dbo].[usp_Testing] 
-- Add the parameters for the stored procedure here
@sONbr nvarchar(50) = NULL,
@SOLine nvarchar(50) = NULL,
@SerialNbr nvarchar(50) = NULL,
@StatusCode nvarchar(50) = NULL,
@PackType nvarchar(50) = NULL,
@PalletID nvarchar(50) = NULL,
@PackingListNo nvarchar(50) = NULL,
@CrDateTime nvarchar(50) = NULL,
@CrUserID nvarchar(50) = NULL,
@return nvarchar(50) = NULL OUTPUT
AS
BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with SELECT statements.
SET NOCOUNT ON;

-- Insert statements for procedure here
IF EXISTS(
            SELECT sONbr , SOLine
            FROM [ABCSystem].[dbo].[NEW_TEST_NUMBER]
            WHERE sONbr = @sONbr AND SOLine = @SOLine
          )
BEGIN
    UPDATE [ABCSystem].[dbo].[NEW_TEST_NUMBER]
    SET     StatusCode = @StatusCode
            ,LastUpdDateTime = GETDATE()
            ,LastUpdUserID = @CrUserID
            ,StatusDesc = 
            CASE @StatusCode WHEN 'N001' THEN 'New'
                             WHEN 'PR001' THEN 'Prepack In Progress'
                             WHEN 'PR002' THEN 'PrePacking Completed'
                             WHEN 'WE002' THEN 'Weight Complete'
            END

            ,PalletID =
            CASE @StatusCode WHEN 'N001' THEN cast(null as nvarchar(50))
            ELSE PalletID
            END

            ,PackType =
            CASE @StatusCode WHEN 'N001' THEN cast(null as nvarchar(50))
            ELSE PackType
            END

            ,JobID =
            CASE @StatusCode WHEN 'N001' THEN  cast(null as nvarchar(50))
            ELSE JobID
            END

            ,JobCrDateTime =
            CASE @StatusCode WHEN 'N001' THEN  cast(null as nvarchar(50))
            ELSE JobCrDateTime
            END

            ,PackingListNo =
            CASE @StatusCode WHEN 'N001' THEN  cast(null as nvarchar(50))
            ELSE PackingListNo
            END

    WHERE sONbr = @sONbr AND SOLine = @SOLine

    IF @@ERROR <> 0
      Set @Return = 'UPDATE FAILED!'
    ELSE
      Set @Return = 'UPDATE SUCCESSFULLY.'
END
ELSE
BEGIN
   Set @Return = 'NO DATA EXIST!'
END