Cloud to Cloud migration with overlapping users

[John Marsh]

We have a corporate instance of Jira cloud (e.g. parent.atlassian.com) that has all our users in it (e.g. user1@parent.com, user2@parent.com).

One department created their own Jira cloud instance (e.g. department.atlassian.com) before the corporate instance was available with some departmental email addresses in them (e.g. user2@department.com). At some point user2@parent.com was invited to use the department instance of Jira so has an account.

We would like to migrate department.atlassian.com into parent.atlassian.com with:

department.atlassian.com               parent.atlassian.com

user2@department.com       ->       user2@parent.com

user2@parent.com               ->       user2@parent.com

Is this possible? How would that be done? We would like to keep all the history if possible.