Provided services have not been completed, they can be moved around within and between appointments by dragging them with the mouse, as follows:
Click on the service name within the treatment plan line, and keeping the left mouse button pressed down, drag the service into the required appointment.
To select multiple services together in the treatment plan, click the first service, then hold down the SHIFT key and click the last service. If the services you wish to select are not adjacent to each other, hold down the CTRL key then click on each service required.
To make it easier to select services that are commonly used together in a Course of Treatment, set them up with adjacent codes in the Services List and group them in service categories.
and click the last service. 
then click on each service required.