1996 windstar lock actuator

I am trying to replace the lock actuator in the passenger door of my 1996 windstar gl. I have all the paneling off but cannot figure out what tool to use to loosen the bolt holding the actuator. It isn't a hex or a torx, as far as I can tell.

Since I got no replies to my problem, I thought I would post the answer. I found out the actuator is secured to the door by a rivet. I had to drill the rivet out and secured the new actuator with a nut and bolt.

I did the same thing. But its not necessary. You can remove the actuator from its mount instead.