This feature allows one organization to be merged into another. For example, if organization A and organization B should really be one organization, merging will change the links from cases, users, timeslips, etc. on organization A to point to organization B. Merging will also merge addresses, organization types, contacts, etc.
Organization A will still have a record in the database. The record will automatically be marked inactive, and contain a note that "This Organization was merged into Organization B on mm/dd/yyyy".
Your user role must have the Merge Organizations permission in Admin > User Roles (Permissions) to use this feature.
The "Merge into Another Organization" link should automatically appear in the Actions menu if your site is using the static organization profile. If your site is using a dynamic profile you likely will need to manually select it in the Actions element's list of processes (edit the dynamic profile, scroll down to the Side/Action Elements section, expand the options for the Side/Actions: Actions element, then select that link).
That link displays a page where you select the organization you want to merge into. If the organization is already scheduled to be merged, you can cancel or perform the merge. Note that an organization merge can be an intensive process, potentially updating thousands of records, so it is best to have them occur during non-business hours.
All scheduled organization merges can be viewed on the Admin > Organization Merge Queue page. You can re-order the entries, cancel merges, and and set the time for the merge to occur.
A history of all merges is available on the Admin > Organization Merge Log page.