When you create an order to purchase item(s), it appears in the order feed. Several travelers may message you for each order. Each chat with a traveler about a specific order is a potential deal, which is assigned a unique ID (displayed at the top of the chat window).
In the chat, you discuss the terms of the deal with the traveler. The terms you agree on may differ from the initial order terms. At the same time, the order may still be displayed in the order feed, as another traveler may message you and offer better terms.
After you have agreed on the deal terms with the traveler and paid for it, you cannot change the terms anymore. You can read about the cases in which you can cancel the order here.
Now you can hide the order from the order feed (as other travelers may still message you about it, but you have already agreed). To do this, click the "Hide order" button inside the order. In the future, if necessary, you can display the order in the feed again by clicking the "Publish order" button.
You may not want to hide the order from the feed. For example, if you want the order to be regular.
It is important to note that deal terms may differ from the initial order terms. The initial terms remain the same and continue to be displayed in the order feed until you decide to change them. At this time, the deal may have its own terms - these amounts are not related to each other.
Thus, you can change the order terms and price at any time. However, you cannot change the terms of an already paid deal. You can read about the cases in which you can do this here.