At the service centre of a large loyalty program in the travel industry, writers in the correspondence department reply to incoming requests and complaints. As a community of practice (Wenger 1998), the writers have formed a practice around their primary focus of identification: the business letter-of-reply genre. The genre is institutionalised and highly stable, yet it also requires constant negotiation and reification. Writing is situated and operationalised, repetitive and dynamic. When the writers first heard of an intentional change to the style in which they wrote their letters, they argued that the genre had changed and was no longer a business letter. This research critically examines textual (e.g. Swales 1990, Lewin et al. 2001) and social aspects (e.g. Miller 1984, Dias et al. 1999, Beaufort 1997) of genre theory to analyse the social context, reactions and learning strategies of the community, and to provide a comparative and contrastive analysis of the textual changes.