EXR Image region option

Hello,
I am trying to find out the way to change global option on openEXR after submit to the render farm through deadline. For this particular project I need to use a hard-coded tool which doesn’t give an option to change any of render settings. I need to change “Image Region” from “save full image” to “save region” under OpenEXR Configuration.
Besides reconstructing the tool, what’s the better way?
Thank you,