To flag your question for re-opening, click on "flag"  at the bottom of the question, near the tag area.  

![enter image description here][1]  

Then in the "Other" section add a message for the moderators.  (It's usually better to be descriptive)

![enter image description here][2]

And click "Flag Question".

If you have at [least 5 reputation](https://askubuntu.com/privileges/participate-in-meta) you can  also [ask a question](http://meta.askubuntu.com/questions/ask) here on meta, asking for your question to be re-opened.


  [1]: https://i.sstatic.net/9fGTm.png
  [2]: https://i.sstatic.net/o8IY0.png