Double sliding glass doors

Thanks for reaching out to us. I have worked on a patio door with two screws that hold the bottom rail on the door. I'm not entirely sure, but it could be a door that was made by "Miller". To access the roller you will need to remove the two screws at each end of the bottom rail. Then using a block of wood and a hammer/mallet, tap the bottom rail off the frame. Make sure you take your time so as not to damage the glass or the frame of the door. 

We've also related some videos on this page that may be helpful. Once you remove the roller assembly, show us some photos and we can work from there.