The scenario that involves a change modeled by a positive number, but an end result modeled by a negative number is:
Anthony starts his dive in a boat 6 feet above sea level. He descends to see a shipwreck 234 feet below sea level.
In this scenario, the change (descent) is modeled by a positive number (the amount he descends, which is 234 feet), while the end result is negative because being below sea level is represented as -234 feet.