Prospect can be changed from 1 campaign to other campaign, it can be shift from campaign>prospect or prospect directly.
Step 1, Select/ Filter the Prospect from list
Step 2, Click on Change Campaign
Step 3, Select the campaign and user
Step 4, Click on "selected" button to shift the prospect or "Select All" to transfer all the prospect.
Note : Subscribed need to ensure the user under campaign on which name prospect getting shifted.