Behavioural Therapy is a very well tried way to change certain habits and behaviour by increasing the frequency of acceptable (wanted) behaviour and decrease the frequency of unacceptable behaviour.
Behaviour Modification is a term that describes this approach with certain programs that have been developed for children, adolescents or adults with ADHD.
The basis of behavioural modification are rewards and consequence structure. Positive feedback (appraisal or any kind of immediate reward) are given for "good" behaviour. So the child will try to increase this behaviour to please the parents (or get the reward).