Forms seeing other forms

Question

I have 2 forms in my app at the moment.  The main form calls another form from a menu option.  I have got that working.  On the second form, when OK is clicked I want to close the from (easy) and make the first form become active again.  But the code is on the btnClick on the second form and I can't seen to access the first from enable or show properties.

So I suppose the question is - how do u make a control on one form access the properties on a different form.

i have tried

frmMain.show()
frmMain.Enable();

but the .show() or .enable() are not appearing on intelli type (or what ever its called).