A user requested merging two accounts, created at different times, for the same platform.
This feature can, at least initially, be developed as a module from person that gets called as a rake task.
To merge them, we need to make sure that we transfer:

• User profile details
  • Identities
  • Access grants
  • Access tokens
  • Oauth applications
• Person profile details
  • Annotations (disciplines, expertise, tools)
  • Group memberships (current, former and favourites)
  • Work groups (current, former and favourites)
  • Projects (current and former) *
  • Programmes
  • Institutions
  • Subscriptions
  • Resources (DataFile, Sop, Model, Document, Publication, Presentation, SampleType, Sample, Event, Investigation, Study, Assay, Strain, Workflow, Collection, FileTemplate, Placeholder, Template) for both roles of:
    • Creator
    • Contributor
  • Policies
  • Permissions
  • Activity Logs
  • Message Logs
  • Admin/gatekeeper roles

• It is possible for people to appear twice in some places, depending on whether they got access through an institution, for example.