Symptoms

I changed a process that links with a SharePoint library in Visual Studio but when I want to deploy it doesn't get deployed.

 

Diagnoses

Created a new process in the same VS solution. Can't rename existing KPRX files and hope that will change the process name, since the DisplayName and SystemName and GUID are recorded in XML inside the file, it won't help to just rename the filename.

 

Resolution

Created a brand new process due to time constraints.

In order to duplicate processes but give them new names, you can download the process from K2 Workspace, here:
K2 Workspace -} Management Console -} K2 server -} Workflow Server -} Processes -} Select your deployed process -} Versions -} Download the required version

After that, extract and open the downloaded file with Visual Studio, then give it a new name and save it as a new file. When that's done, you can deploy it with the new name and it should generate a new GUID system name, then you can use P&D tool to package this new process and send it across to production / QA and deploy it there.