If you want the prospects to be removed from the list of leads then they can be archived. You should have the correct permission for this:
Please Note: Clients can not be archived in bulk.
Follow the following steps to archive the prospects.
Step 1: Select Clients from the dashboard
Step 2: Select Prospects
Step 3: Select the Prospects from the list that you want to archive simply by clicking the check box.
Step 4: Select the Bulk Archive tab on the top left corner.
Step 5: Select the Accept tab.
Step 6: The archived prospects will now be listed in the Archive list