Child form back to parent

Question

Ok,

Form1 creates and opens Form2
Form2 then needs to pass a string back to Form1.

Its like this,
Form1:
public void fromForm2(string incomingString)
{
      MessageBox.Show(incomingString);
}

Form2:
 public void passToForm1(string something)
{
      //   I think I need something like this? I dont know
      this.Parent.fromForm2(something)
}