Once you have requested an instant job and you need to edit it, you need to click on the 'Ongoing' section in your dashboard and then click on the three dots (···) to see this menu:
Step 1: Click in 'Ongoing'
Step 2: Click on the #number to reveal the window.
Step 3: Click on the ··· dots.
This functionality allows you to edit either the pick-up or drop-off details. It doesn't allow to change pick-up/drop-off times.
For a scheduled job there is no option to edit in the web version via the dashboard, therefore, you will need to access the client app and reschedule from the mobile phone or tablet. Another option using the dashboard is cancelling and requesting a new scheduled delivery.
You're also able to call the driver anytime you need to within he accepts the order and when the order is marked as finished, and after that, you've still the phone number on the app.