Answer:
A retroactive date endorsement
Step-by-step explanation:
In Insurance, a retroactive date endorsement is used for most claims-made policy forms.
For a claims-made policies, the date which a professional liability coverage begins, covering for any incident that causes damage or harm to a third party on or after the date it occurred, provided the claims relating to it were filed with an active liability insurance coverage, is known as the retroactive date endorsement.
Hence, Bernice should add a retroactive date endorsement to the policy to protect the insurer against liability for such previous losses.