What is the easiest way to disable an oacore server in a DEV environment?

Hi

I wonder if anyone can give me some advice with the following problem.

Our PROD environment has 3 oacore servers, and when we clone to our DEV environment we are getting 3 oacore servers for each DEV instance,
and this is causing a memory issue on our DEV web server.

I would like to delete/disable one of the oacore servers in a DEV environment to free up some memory.

I have tried the following;

1) I used the instructions in Doc ID 1905593.1, section "4.4.2 Removing a managed server".
namely: "perl $AD_TOP/patch/115/bin/adProvisionEBS.pl ebs-delete-managedserver .. etc"

Everything went well until I attempted to apply a patch, and then I encountered the following error;