Beneficial interest declaration requires partners with unregistered contributions to notify the LLP and disclose detailed identity and interest particulars. Form 4C requires a partner holding or acquiring a beneficial interest not entered in the Register of Partners to declare identifying particulars and the existence of the beneficial interest registered in another's name, and to disclose the registered partner's details, creation/acquisition date, mode and nature of the interest, reasons for non registration, instruments evidencing creation or transfer, any transferor's particulars, and particulars of subsequent changes, attaching identity proofs and relevant instruments.