How do I open this ZIF? Connector?

Hi,

This is the underside of top of my D600 that I dropped. To mend the top display I had to remove this board and do some soldering.

I pulled out the ribbon that goes into the white connector at the bottom of the board as you view it - see attached photos.

I pushed back the ribbon, although it did no go completely in. After re-assembling the camera I found the wheel under the forefinger inperative.

How do I unlock this, I have so far not tried too hard as I must not break it!

hope someone can help,

John