We would all like to be able to extend the lenght of a campaign, even more so when there's not much missing for it to succeed. However, changing the duration of an ongoing campaign means failing to meet the originally announced deadline.
This modification may seem harmless, but in France (where Animal Webaction is registered), this type of practice is considered as fraud, which is sanctioned by law.
It is therefore legally impossible for us to extend the duration of a campaign, whatever its state of progress.