I want to change the epic status in parallel to the subtasks moved to done status

Question

Dear Community,

As I was struck in the automation part,  anybody kindly help with the given requirement, it would be very much appreciated.

Requirement:

I need to change the Epic status to the next status when the subtasks moved to done status

Detail explanation
 We have a business project in the Jira work Management, By using form we can create the Epics. The workflow will flows through the some Milestones. 
By using Automation Rules , I have created the subtasks  under the Every Milestone , Here we can take Milestone as Task.
FYI
Mile stones 1(Task) 
Subtaks1
subtask2
subtask3
Milestone 2(Task)
Subtask 1
subtask2
and so on...

Now the exact requirement is once the epic created , the status of the epic is "Milestone 1"
after moving the all the subtasks into  done status, the epic status has to changed Milestone 2, Like wise, all the subtask under "Milesotne2" were moved to done status, then Epic status has to moved to "Milestone3"

Like wise customer is expecting

Any kind help in this regard, thanks in advance

Regards,
SuneelBabu

John Funk · Answer

I understand, and that's what I suggested to you in my first answer. What will not work with that?

suneel babu · Answer

Hi John,
Thanks for your quick response,

The exact requirement is once the epic created , the status of the epic is "Milestone 1" under Milestones1 Some subtasks has been created, Under Milestone2 some Subtasks has been created by using automation rule  and so on... 
after moving the all the subtasks into  done status under Milestone1, the epic status has to changed Milestone 2, and Under all the subtasks moved to done status, The epic status from Milestone2 to Milestone3 Like wise,  Customer is expecting"

Now  I hope you understand the exact requirement.

Can you provide me automation diagram for this requirement.

Thanks in advance,
Suneel Babu

John Funk · Answer

Hi SuneelBabu - Welcome to the Atlassian Community!

I assume that you would want to change the Milestone 1 to Done when the Sub-tasks are done. Correct? So do the automation for that first.

Then build a second rule that is based on Milestone 1 transitioning to Done. I would actually create Components for Milestone 1 and Milestone 2 to make it easier for the Conditions in the rule. Be sure to check the box on the Rule Details page of the second rule to allow other rules to trigger this one.