Final answer:
Social Skill Training is the intervention where children learn to relate to others and develop social skills to make and keep friends.
Step-by-step explanation:
The intervention in which children who have trouble making and keeping friends learn to relate to others is called Social Skill Training. Social Skill Training helps children develop the necessary skills and strategies to interact effectively with their peers and form meaningful friendships. Through this intervention, children learn important social cues, problem-solving techniques, and communication skills that can enhance their ability to build and maintain relationships.