In Berry's (1981) classic work on exchange structure, it was argued that knowledge exchanges consist of some conversational participant who already knows the information and some conversational participant to whom the information is imparted. The former participant is commonly termed the primary knower, whereas the latter is termed the secondary knower. What is missing in Berry's model (and work that has extended Berry's model), however, is (1) an explanation of how rights and access to knowledge can be claimed or resisted on a turn-by-turn and move-by-move basis, and (2) a more elaborated conception of knowledge that goes beyond a sender/receiver model of information. Drawing from a corpus of spoken conversation from diverse sources, I extend Berry's model by showing how a participant's 'knower status' is often negotiated within an exchange. As an interpersonal resource, knowledge can be asserted, challenged, resisted, accepted, expanded, upgraded, downgraded, etc. Furthermore, I argue that 'knowledge' should be given a social/practical epistemological interpretation; from this perspective, knowledge is associated with a speaker's degree of access to information and with a speaker's rights and obligations to know.