Locally in the office I use subnet 192.168.1.0/24. Now we have added an operator that gives the same local network and of course they conflict.
Is there some way i can get around this programmatically or will i have to replace the local subnet?
Yes, you have to change it. Routing rules that try to say "from 192.168.1.0/24 to 192.168.1.0/24" will result either in loops or dead-ends.
The only way this is difficult is if you haven't got DNS set up locally and have a bunch of references to raw IPs. If everyone's referring to hosts by name, all you have to do is change the DHCP and DNS, then restart everything.
If you haven't done that before, now you have an incentive to get it done.