Let me start with little background. My team believes in XP practices and follow them religiously. We also followed Scrum process and use to switch our pair at the end of sprint after sprint review. It was going all smooth till that one day, when we decided to ditch Scrum and adapt Kanban as our delivery model.
We thought we will change pair after each story but stumbled upon issues, since each pair was starting and finishing at different times. We struggled for a while and then came up one idea. We decided to switch the pairs every week and made one-person owner of the story. Owner took the story with them while switching the pair.
Bingo! Our problem was solved for time being.