How to keep the current assignee when the status is changed to DONE?

[Carmen Viejo]

Currently, when a developer working on a ticket completes it they change the status to DONE, and the ticket goes back to the original reported (for example, the product manager). Is this by default? We would like the ticket stay assigned to the developer when the status is changed to DONE. 

[Aron Gombas _Midori_]

The behavior you described is definitely NOT default. Actually, the default is that the assignee remains unchanged.

I'd think that one of these are true:

1. Either your workflow is configured to do this (the transition that moves to "Done" has a post function that updates the "assignee" field)
2. Or there is automation rule implemented with AFJ that does this
3. Or there is a script (e.g. a Groovy script executed by ScriptRunner) that does this

[Deleted user]

By your description it sounds like there may be a "post function" associated to the transition to done. 

You would need to go into your workflow and identify the transition to "Done". Look in the post function settings and see if there is a post function that "Assign to Reporter"