What controls whether or not story points can be updated for a story within a sprint?

[Steven Kahrs]

We run several separate (and all licensed) instances of JIRA here and in one of them we find we are able to update story points on stories in active sprints and in another instance we find that we cannot do so.  In that latter case, we pull the story out of the sprint, update the story points, and then put it back in the sprint.  We have not found the setting that allows story points to be updated in the former case and prevents it in the latter case.  Can someone point us in the right direction?  Thanks!

[Nic Brough -Adaptavist-]

I can only think of two ways to do this, one involves hacking (can you check your "system information" page for "changed files"?) and the other assumes that when you say "pull story out of sprint" you are changing the underlying status of the issue - is that true?