When you have completed a call using the power dialer, the power dialer buffer will kick in and wait to proceed until the buffer time ends. With that, you will have the option to pause the buffer time to continue taking notes about your most recent call, exit the power dialer completely, or auto-initiate the next call with the click of a button.
The banner across the bottom of the screen, as shown below, will appear once a call has been finished when using the power dialer. You may proceed to wait until the buffer time ends, or take any other you'd like to move on to your next task.