In the Edenred+ app:
Select the CESU tab, then Manage my CESU,
Select My beneficiaries to view your beneficiary list,
Select the Delete icon (🗑) next to the beneficiary that you'd like to delete.
Your selected beneficiary will then be deleted.
If you'd like to add a beneficary to your account, see How do I add a service provider to my beneficiary list?