If a merge is canceled in the queue, the lookup value will still be marked inactive and must be manually changed to active if it should still appear in dropdown lists on forms.
Once completed, merges cannot be undone. Reversing the effect of a merge may be possible by restoring data from a backup. However, that can only be done by PS Technologies, is a chargeable action, and can only restore the data as it was at the time of the backup.
Marking a lookup value inactive preserves existing data. Merging a lookup value into another one changes existing data, and generally cannot be undone, as explained in Merging Lookups section.
Example: A site has "Transgender" as a lookup value for the Gender field, as required by a specific funder. If the agency no longer has that funding, and does not want to continue to use Transgender, but needs to be able to report on the number of cases that have that value, the Transgender value should be marked inactive, not merged into another value.
Exporting and Importing System Lookup Values between Sites
The values in a system lookup list can be exported from one site and imported into another, for example from a demo site to a live site, or from one agency's site to another agency's site. Custom lookup lists cannot be exported and imported.
Your user role needs the "Import and Export Lookup Values" permission to use this feature.
To export a list, display it, then use Actions menu > Export Values link. This will download a "json" file. If the lookup being exported is Race, the file will be named "race.json".
All values in a list are exported, including inactive ones. You may want to clean up a list by merging inactive values before exporting.
Each lookup value's attributes are exported; including the name, whether the value is active or inactive, whether it is a 'system' value, and the LegalserverIndex ID it is mapped to (if applicable). This means that an inactive lookup value will be imported as inactive.
To import one or more lookup lists, display any lookup list, then use the Actions menu Import Lookups link to display the page where up to 5 files can be uploaded: