By tapping on a nearby building, you will be presented with the Request for Access screen:

Figure 3.6. Request Access

Here, you can request access to a destination you otherwise would not have access to. Request for Access does not call a car. After you supply the reason for why you ought to be granted access and tap Submit, building security will be notified of the request. Once building security approves or denies the request, you will receive a push notification of the outcome. If you have already submitted a request for access to a building that is still pending, you will receive an error if you try to submit another one.

You can see your history of requesting access at various buildings by tapping on your Avatar and tapping the LiftOff Requests menu item. You will be presented with the list of buildings with which you have requested access and the outcome of the request.