When updating the prospects list, you provide it with the latest information about the prospects it shows.
To update the prospects list:
Open a building. For more information on how to do so, see section 4.6.1., 5.4.3. or 6.1.1.
Go to the building card (see image below).
Click the tab called "Prospect" (see image below). Within the tab called "Prospect" you will find a prospects list. In the prospects list you will find active prospects for the building you are working with.
Click "Update list" (see the first image below). When you do so, the prospects list will be updated (see the second image below).