Read Only Config - Want to add AllowEncodedSlashes On

I am using Pydio Cells application behind Sophos XG WAF. Most things are working but certain functionality is broken. Per the Pydio Cells documentation I need to have the following in my reverse proxy:

AllowEncodedSlashes On

This file /usr/apache/conf/httpd.conf contains:
Include /cfs/waf/reverseproxy.conf

I want to edit /cfs/waf/reverseproxy.conf as it is where my WAF is defined but it is read only. 

SFVH_SO01_SFOS 17.5.9 MR-9# ls -la
drwxrwxrwt    6 root     0             4096 Jan  5 05:57 .
drwxrwxrwt   67 root     0             4096 Jan  5 05:57 ..
-r-xr--r--    1 root     0              255 Jan  8 11:02 mpm.conf
-r-xr--r--    1 root     0            16691 Jan  8 11:02 reverseproxy.conf
-r-xr--r--    1 root     0              360 Jan  8 11:02 status.conf
drwxrwxrwt    3 root     0             4096 Jan  5 05:57 waf

I have tried these which I found on the forum:
mount -o remount,rw /
mount -no remount,rw /

but I can't get /cfs/waf/reverseproxy.conf to be editable. I know that any changes I make will be overwritten if I use the UI or apply a Sophos XG update. I am fine with that just to get a working Pydio Cells. 

Can anyone help me get that file editable?

thanks,