The only way to do it and ensure you do not damage the trim is with a trim removal tool. You may be able to get this at an auto parts store but for sure you can get it from Eastwoods.
Basically it looks like a thin blade on a handle with the tip that looks like a wide shallow arrow head. You slip the tool between the trim and glass and angle it so one side of the arrow head is parralell with the trim. Slide it along until it catches one of the clips and rock the tool back onto it's point to release the clip. Continue all the way around the window.
It may take awhile to get the feel and if there is a build up of crud under the trim the clips may fight you but it's the only way to do it without denting or distorting the trim.