If do you want to editing your "Cellular Data Network", you have to:

1- Install on Cydia => APN Editing

or

2- Settings => Reset => Reset Network Settings

or

3- If these two options did´t work, it´s because your sim card block the option "Cellular Data Network". So you have to do this:

a-Put a sim card that allow editing this data
b-Go to Settings => Network => Cellular Data Network
c-In the Cellular Data Network screen => Put your sim card => Back => Cellular Data Network again => Now you can edit these settings!

But probably if your sim card block the option, when you leave the Cellular Data Network, your sim card will update the informations again.