If the change requested for a specific problem is completed and closed, you can close the problem (and all the other problems that might be linked to the change). If no change is associated with a problem, you can close it once it is resolved.
A problem can be closed by either of these two methods:
Click on More in the top-right corner of the problem’s detailed view and click Close.
Click on the Status drop-down and select Closed. Then click on Update.