To change the phone number associated with your Postmates account, please open the Postmates iOS app, tap on the settings cog in the top left hand corner, tap on “Contact Info” and update your phone number on this screen. To update on your Android App or via the website, go to your Account Details screen under settings and update your phone number here.
Please note that it is possible for a phone number to be set per delivery address as well. If you want to update the phone number attached to a specific delivery address, when you are on the checkout screen and selecting an address you can tap on the address to edit all specifications including the phone number.