In the Workflow Designer, it is possible for one to duplicate existing process under the same package using the option available in the process's properties.
Figure 1: Duplicate Process
Since the design is made up using XML, we may inspect on what is going on behind the scene.
Figure 2: Duplicated Process as "process1"
Figure 3: Both processes share the same set of participants
Take note that both processes would still use the same of of participants. Modifying the name or removal of participant at any of the processes may affect all other processes that uses the particular participant.