Update rows in Database using XML data

Hi,

This is the first time I am using XML to insert data into a table.I am saving the data from the front end(all the Datagridview rows) into an xml file and sending it to database to insert into table SD_ShippingDetails.Below is the Query for reading the XML data and saving data.As you can see from the Query I am deleting the related ShippingID details and inserting again.(DELETE FROM SD_ShippingDetails WHERE ShippingID=@ShippingID).Can we update already existing rows in the SD_ShippingDetails by getting the data from XML.If Yes,Please help me with the query.

CREATE PROCEDURE SD_Insert_ShippingDetails    
    @PBMXML as varchar(Max),      
    @ShippingID as INT      
          
    AS      
    BEGIn      
          
          
    declare @i int      
          
    exec sp_xml_preparedocument @i output,@PBMXML      
          
        
    DELETE FROM SD_ShippingDetails WHERE ShippingID=@ShippingID      
          
    INSERT INTO  SD_ShippingDetails(ShippingID,Weight,Height,TotalBoxes,Price)      
    SELECT ShippingID,Weight,Height,TotalBoxes,Price FROM OPENXML(@i,'Root/ShippingBox',2)      
    WITH (      
    ShippingID int,Weight varchar(20),Height varchar(20),TotalBoxes varchar(20),Price numeric(18,2))    
        
          
          
    exec sp_xml_removedocument @i      
          
    END 

Thanks.