Hi desus,
If you want to edit existing graphs, you can un-group it and then manually adjust it, however un-grouping does not allow to edit data. I would suggest you to check these links:
How do you ungroup or expand a pie chart in Adobe Illustrator CS6?
How do I resize a graph?
I hope you would get some insight and this would help you to understand how you need to go about. If you still need assistance, feel free to report with your workflow and screenshot of how you want to edit the graphs.
Regards,
Om