To update the fields of an organization, click on the CRM module (at Global level) -> Organizations. Click on the Actions menu of the one you wish to edit and select "Update field"
A pop-up window will then appear, allowing you to change the value of any field. Make sure to click on ‘Apply’ to see the changes appear.
You can also edit these fields in the organization's detailed view (by clicking on it in the organizations' list).