I'm helping install a wood core metal clad exterior door. The problem is that the opening isn't standard size. The owner has already put the frame in & when he did he removed the top of the door frame. Now the door needs to be trimmed to fit.(The top needs to be cut to line up the hinges) The walls are block & the floor is wood. Can the door be cut @ the top, & what is the best tool to do this with? Thanks Sooooo Much !