Change existing workflow in JBPM

[Ganesh Ashtakar]

Hi,
I am new to JBPM, I am having one existing workflow but much of the java code embedded in xml. Now for the application requirement I want to change the existing workflow such that remove maximum possible java code from workflow and put it in some helper class. But this modification as per my knowledge will cause a huge problem for application.

So can someone tell me how can I deploy the changed workflow as JBPM does not support for changed ProcessDefinitions (workflows).

Thanks in advance.
Ganesh.