I'm working on a project where we branch off of develop for each feature and once the work is done a pull request is made as usual. 

I'm wondering if later on I find I want to make some changes to how I implemented the feature is it better to just make a new branch or, since it's still dealing with that feature, to checkout that branch, merge with develop, make changes and then resubmit a pull request? What is best practice in this situation?