difficulty closing parent form and creating a new one (when child form closes)

[jonny_chympo]

Briefly:
Hi, I have a form A that opens a child form B (by clicking a button in form A). In form B, data is updated and form B is closed when the OK button is clicked. Because of the way I've implemented my database I need to create a new form A and delete the old one when form B closes - this will ensure my data is updated in form A.

I have tried the following (which makes sense in my head) but when I click the OK button on the NewPatientForm (form B), both form A and B close without displaying a new form A:

//Form A
public partial class EPTForm : Form
    {
        public EPTForm()
        {
            InitializeComponent();
        }

        private void btnNewPatient_Click(object sender, EventArgs e)
        {
            NewPatientForm frm = new NewPatientForm(this);
            frm.ShowDialog();
        }
    }

//Form B
public partial class NewPatientForm : Form
    {
        EPTForm frmEptFormInstance = null;

        public NewPatientForm(EPTForm frm)
        {
            InitializeComponent();
            this.frmEptFormInstance = frm;
        }

        private void btnOk_Click(object sender, EventArgs e)
        {
            this.Close();
        }

        private void NewPatientForm_FormClosing(object sender, FormClosingEventArgs e)
        {
            this.frmEptFormInstance.Close();

            EPTForm eptFrm = new EPTForm();
            eptFrm.Show();
        }
    }

I hope this explanation is clear enough, please let me know if you need clarification. Thanks for any help anyone can provide!