I am a professor of child and adolescent psychiatry in Glasgow. In my Fellowship, I investigated radical system change in Bucharest and New Orleans. I learned how Romania had moved rapidly from institutional care to foster care for children who had experienced abandonment or maltreatment. In New Orleans, I learned how an Infant Mental Health (IMH) approach had been brought into the social care and judicial systems supporting children coming into foster care. I was interested in this because, working in the UK NHS, I saw that radical change was needed to integrate IMH approaches into social care for the young children who most need it. Since my Fellowship, I have launched a randomised controlled trial of the New Orleans IMH model which has led to the Scottish Government committing permanent funding for IMH services throughout the Scottish NHS. My Fellowship was a unique opportunity to learn that, across the world, radical service change depends on the development of strong and trusting relationships between individuals working in different professional contexts. It is the meetings I have with colleagues, and the relationships we build, that eventually make radical change happen.