From time to time, you may find a lead that has a linked sibling that is not in fact the lead's sibling. This can happen when a parent/guardian completes the form on behalf of another family (due to language barriers etc.)
Move all parents/guardians that are not associated to the lead, to a new family:
On the pop-up window, choose 'create new family'
This will move the parent/guardian into a new seperate family on the lead eg:
You can then move any other parents that are not related into this new family you created (the new family will show up in the dropdown, you need to choose this instead of creating a new family).
Check that only the correct parents/guardians are showing in Family 1.
Unlink the families showing on the lead with the incorrect parents/guardians:
Now that the leads have different parents, they will be unlinked as siblings.
Don't forget, if there are multiple parents/guardians showing on the lead that are duplicate records, these can be merged together, instead of unlinking them: