How to Edit Post Process Material Parameter

I’m using a Post Process Material to adjust the in-game Gamma. I would like to give the player the option to adjust the Gamma (like a slider). The only problem I’m having is I have no idea on how to edit a post process material’s parameters. I know how to do this for regular materials, but that method doesn’t seem to work for post process materials. I cannot find out how to obtain a dynamic instance of the material, so I can edit it using Blueprints. Any help is greatly appreciated. I’ll post a picture of the material.