How to "unresolve" issues in JIRA?

[Markus]

It happens sometimes that people move an issue to "Done" or "Close", the resolution screen appears they select a resolution and the issue gets resolved.

Good. BUT sometimes people figure out that the issue is still not finished and they move it again to "in Progress". Is there a way to unresolve an issue? Or something like a reopen screen?

PS: Sure its bad pactrice and we are teaching the people to stop doing those kind of things. 

[Thomas Schlegel]

Hi @Markus,

you have to add a postfunction "Update Issue Field" to your workflow transition which re-opens the issue. Within this postfunction you should clear the resolution field.

[Chris Nicosia]

You can also use the clear field value post function

[Ben Lorenzo]

Hello, I'm new here and imported a bunch of tickets to Jira and they came through as "resolved" and are not.

Where can I get more info on this postfunction workflow stuff?

thank you