Open response assessments have due dates fixed by the course team. Each step has its own due date which cannot be extended.
On the open response assessment page, the due date is displayed next to the title of each step as due Month Day, Year 24-hour Datetime with a countdown in parentheses.
For example, due November 8, 2023 18:59 EST means the submission is due November 8, 2023 at 6:59pm Eastern Time.
On the Dates tab, the due date will show on the schedule as Weekday, Month Day, Year and the 12-hour datetime. For example, the above would show as due Wed, Nov 6, 2023 6:59pm EST.
The due date is set in UTC by default, but you can ensure it's showing in your local timezone by updating your Site Preferences.