When a problem of understanding arises for a hearing-impaired recipient in the course of a conversation, and is detected, repairing that problem is only one of several possible courses of action for participants. Another possibility is the collaborative closing of the part of the conversation which has proved problematic for understanding, to allow the initiation of a new, and potentially less problematic, topic. This paper examines one practice utilised by hearing-impaired interactants and their partners in achieving such closings. The action of withdrawal of engagement (via withdrawal of gaze at partner) by hearing impaired interactants, accompanied by their production of multi-unit turns at talk, brings about the closing of problematic sequences. It is proposed that these multi-unit turns address the interactional delicacy of recipients' withdrawal of engagement at points where the speaker's action is demonstrably incomplete. By initiating and cooperating with "strategic" topic change in this way, participants act both to conceal the understanding problem and to avoid its potential consequences for the unfolding conversation. In doing so, they also act to keep issues of conversational competence, and the threats to face and identity which may arise from these issues, off the surface of the conversation.