A shipper can still change a delivery job after you have won it. Some of those changes wait for your response: a new pickup time, a pickup point more than 3 miles from the old one, a different vehicle, or new equipment. The app shows the old version against the new one, with Accept and Decline. For changes in equipment requirements, the screen reads Requirements changed to and lists what the job asks for now.
Until you answer, the job keeps the terms you won it at. If you don't respond, the delivery job becomes available again on the Offers page a day before the pickup.
Stops are different. A shipper can add or remove stops until the first stop on the delivery job is completed. Adding or removing stops updates the route and the payment for that delivery job, so the amount shown in the app reflects the change. A notification will tell you that the payment may have changed, and the updated amount appears in the app.