public delegate void SendFromForm1(string Text);
public SendFromForm1 Form1Sender;
private void doctorUpdateBtn_Click(object sender, EventArgs e)
{
    try
    {

        UpdateDoctor DocUpdate = new UpdateDoctor();
        this.Form1Sender(Global.DoctorUser);
        DocUpdate.ShowDialog();

    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.ToString());
    }
}

private void UpdateDoctor_Load(object sender, EventArgs e)
    {
        try
        {
            Form1 abc = new Form1();
            abc.Form1Sender = new Form1.SendFromForm1(LoadInformation);
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.ToString());
        }
}