OK so I've got a bit further with the issue below. If I change the 'Run As' in the properties of the event ,which updates the calendar, to a specified user account (process 1), it kicks off process 2 as that user (so works). My issue now is how to 'softcode' this 'Run As' functionality so that the value is configurable when moving through environments (I have tried and failed to update it in the code behind).  Thank you.

I have scheduled a process which updates a SharePoint calendar item.  The update event on this calendar kicks off a second process.

When I update a calendar item manually it successfully kicks off the second process.  When I use my first process to update the calendar (either using the schedule or manually starting from Workspace), process 1 runs successfully, process 2 errors with the following error:

An error occurred while executing the following method: StartNewProcess

The following error occurred while trying to start the process PROCESS2:

24408 K2:NT AUTHORITYNETWORK SERVICE from ip address :28797 does not have rights to Start Process PROCESS2

I’m not sure where it’s getting the NETWORK SERVICE account from. The SharePoint app pool is set to a domain administrator account which is also the account that runs the K2 service. 

Thank you for any help.