delete pelo windows form

Pessoal tenho o codigo abaixo, para select ele funciona bem mas como uso ele para DELETE E UPDATE

public partial class Form1 : Form
{
SqlConnection dbconnection;//ele prove a conexÆo com o banco igual ao mysql_connection

SqlCommand dbcommand;//linguagem de comunica‡Æo

 SqlDataReader dbdatareader;//Ler todos os dados que obtive do select igual ao mysql_query

 public Form1()

 {
 InitializeComponent();
 }

 private void Form1_Load(object sender, EventArgs e)
 {
 dbconnection = new SqlConnection("Data Source=CPD06;Initial Catalog=NorthWind;Integrated Security=True");
 dbconnection.Open(); //Aqui ‚ aberta a conexÆo

 dbcommand = new SqlCommand("SELECT * FROM Employees where LastName = 'Davolio'", dbconnection);
 dbdatareader = dbcommand.ExecuteReader();