subendorse
/ˌsʌbɛnˈdɔrs/Definitions
1. verb
to endorse or guarantee the endorsement of a person, thing, or idea, especially as an agent or representative
“The insurance company may subendorse the policy to ensure its validity.”
2. noun
an endorsement or guarantee by one party of the endorsement of another, especially in insurance contracts
“The subendorsement clause is essential to understand when purchasing an insurance policy.”