Can recall frmLogIn ?

Question

suppose, I've program includes 2 frmLogIn  and frmMain, the syntax recall frmLogIn in frmMain how ? you see my code below:

in Program.cs file
[CODE]
...
Application.Run(new frmLogIn());
[/CODE]

in frmLogIn.cs file
[CODE]
private void CmdLogIn_Click(object sender, EventArgs e)
{
    ...
    this.Hide();                                 // of frmLogIn
    this.DialogResult = DialogResult.OK; // of frmLogIn

    frmMain _frmMain = new frmMain();
    _frmMain.Activate();
    _frmMain.Show();
}
[/CODE]

in frmMain.cs file
[CODE]
    /* // Don't called frmLogIn in this way
        // If called frmLogIn in this way will be 2 frmLogIn in memory
    frmLogIn _frmLogIn = new frmLogIn();
    _frmLogIn.Activate();               
    _frmLogIn.Show();
    */
   
    // I want recall frmLogIn in here, the syntax recall frmLogIn how ?
[/CODE]