After you submit a demand in the Demand Collection phase of a tender, you're allowed to edit it if you change your mind. However, editing your demand is only possible while the collection phase is still open. After closure, your demand can no longer be modified.
To edit your demand, do as follows:
1. Log into your account;
2. Click on "AggregateEU" on the top blue menu;
3. Click on "Demands;"
4. Now, click on "My Demands;"
5. On the Demand Overview page, click on "Edit" in the tile of the relevant demand;
4. Then, on the editing page, make the changes you desire. You can modify the (1) quantity of gas requested for each specific calendar month and (2) add or delete months. You cannot, however, change the location or the buyer status while editing. If you want to change those details, you must withdraw the demand entirely.
5. Finally, click on "Submit" to save your changes.