Calling a method from a different form

Hi,

I have two forms in a C# application. One called frmMessages and the second frmAdmin.
On the frmMessage form I have a menu called moveToToolStripMenuItem, which I need to make invisible from frmAdmin.
I created the following public method on frmMessages:

public void ShowHideMenu()
        {
            ToolStripMenuItem item = new ToolStripMenuItem();
            item = this.moveToToolStripMenuItem;
           
            if (item.Visible == true)
            {
                item.Visible = false;
            }
           
        }

In frmAdmin I created a button that calls the above method:

 private void button1_Click(object sender, EventArgs e)
            {
                frmMessage Frm = new frmMessage();
                Frm.ShowHideMenu();

            }

I need help understanding why this code is not working. Thank you.