Phenomenon: In higher education, reflection sessions are often used when participants learn in the workplace. In the Netherlands, all General Practitioner training programs include regular meetings called Exchange of Experiences, in which General Practitioner trainees are expected to learn collaboratively from their own and one another's experiences. Despite this being common practice, we found little research into the structure and process of these sessions. The purpose of this study is to describe the structure and characteristics of group reflection by describing transitions in interactions. We aim to describe the tutor's role in some detail, as this could lead to faculty development. Approach: In medical education, reflection is often approached from a cognitive perspective. However, learning in a group is also an interactional achievement. It is therefore relevant to study the sequential nature of group interaction in collaborative reflective practice. We have used conversation analysis to study the reflection meetings, zooming in on the transition between case presentation and discussion, focusing on the role of each of the participants in these transitions. Findings: The transitions were conversationally complex. Three interactional aspects recurred in the meetings. First, the transitions can be characterized as ambiguous, as there is ambiguity about what will happen next and the floor is open. Second, transitions are an arena for negotiations between case presenter, participants, and tutors, in which knowledge and the right to take the floor (epistemics) play an important part. Third, the tutor can have different interactional roles, namely, that of teacher, expert, facilitator, and active participant. The role of the tutor is important as the tutor's interactional behavior is part of the hidden curriculum. Insights: Conversation analysis focuses on the interaction in group learning and shows how the interaction is part of what is learned and how learning takes place. Transitions are the “messy” moments in interaction yet can tell a lot about the way in which group participants relate to one another. Being conscious of how the floor is taken, the tutor's roles, and the way negotiations take place could help medical educators in the way they shape collaborative learning sessions.