How to copy value from Sub-task to Epic in hierarchy Epic>Story>Sub-task using SIL / Power Scripts?

[jakubiad]

Hi, 

Is it possible to copy field value from Sub-task to Epic with created hierarchy Epic>Story>Sub-task? The case I have is to set Blocked status, when Sub-task is blocked and provide comment. Unfortunately I'm limited to JSU Automation and JJupin/Power Scripts plugins (Jira Server) and didn't find anything helpful in examples and Cprime documentation.