[Ubuntu 16.04]

I'm using simpleproxy for various things, but today I faced something I've never had to do before, trying to remove and change connections..

Normally I just set it up with this:

simpleproxy -d -L 1.2.3.4:5001 -R 4.3.2.1:5002

And simpleproxy will act as a proxy when connecting to 1.2.3.4:5001 and tunnel me to 4.3.2.1:5002.

And when I did changes, I normally just rebooted ubuntu, but now, I need to change some of these connections, without rebooting.

I tried to use etc simpleproxy -d -L 1.2.3.4:5001 -R 0.0.0.0:1000 to disable the connection but that didn't work at all, and it's a horror googling simpleproxy as you get results from everything else.

So please, how do I edit/shutdown exiting tunnels?
Thanks in advance!