this clause shall be construed or mean that losses under this insurance are not recoverable until the Insured's ultimate net loss has been finally ascertained. Inasmuch as this policy is excess coverage, the Insured's right of recovery against any person or other entity cannot always be exclusively subrogated to us. It is therefore understood and agreed that in case of any payment hereunder, we shall act in concert with all other interests (including the Insured's) concerned in the exercise of such rights of recovery. The apportioning of any amounts which may be so recovered shall follow the principle that any interests (including the Insured's) that shall have paid an amount over and above any payment hereunder, shall first be reimbursed up to the amount paid by them. We shall then be reimbursed out of any balance then remaining, up to the amount paid hereunder. Lastly, the interests (including the Insured's) of whom this coverage is excess are entitled to claim the residue, if any. Expense necessary to the recovery of any such amounts shall be apportioned between the interests (including the Insured's) concerned in the ratio of their respective recoveries as finally settled.

4. Notice of Occurrence, Claim, or Suit

A. The first Named Insured shall immediately notify us in writing of any occurrence which may reasonably be expected to result in a claim against this policy. The first Named Insured will notify us on the assumption that an Insured is liable and that an Insured is liable for any amount claimed. Notice shall include:

1. how, when and where the occurrence took place; and
2. the names and addresses of any injured persons and any witnesses.

B. 1. The first Named Insured shall immediately notify us in writing of any claim, alone or in combination with any other claims, to which this policy applies which may exceed 25% of the applicable amount set forth in the Schedule of Underlying Insurance. The first Named Insured will notify us on the assumption that an Insured is liable and that an Insured is liable for any amount(s) claimed.

2. As respects B.1. above, the first Named Insured and any other involved Insured must:
a) immediately send us copies of any demands, notices, summonses or other legal papers received in connection with the claim or suit;
b) authorize us to obtain records and other information;
c) cooperate with us in the investigation, settlement or defense of the claim or suit; and
d) assist us, upon our request, in the enforcement or any right against any person or organization which may be liable to the Insured because of injury to which this insurance may also apply.

3. No Insureds will, except at their own cost, voluntarily make a payment, assume any obligation, or incur any expense other than for first aid, without our consent.

5. Premium - It is agreed that should any alteration be made in the premium for the underlying policy during the period of this policy, or if there is an increase in the risk assumed by the Company, then the premium hereon may be adjusted accordingly.

If this policy is subject to audit adjustment, the premium will be based upon the rating base as set forth in the Declarations. Upon notice to the Named Insured of the earned premium due, such premium in excess of the advance premium shall become due and payable. If the total earned premium is less than the premium previously paid, the Company shall return to the Insured the unearned portion paid by the Insured, subject however to any Minimum Premium stated in the Declarations.

6. Cancellation - This policy may be cancelled by the Insured by surrender thereof to us or any of our authorized agents, or by mailing to us or any of our authorized agents, written notice stating when thereafter such cancellation shall be effective. The policy may be cancelled by us by mailing to the Insured at the address shown in the Declarations written notice stating when, not less than thirty (30) days thereafter (ten (10) days with respect to cancellation for non-payment of premium) such cancellation shall be effective. Proof of mailing of notice as aforesaid shall be sufficient proof of notice. The time of surrender or the effective date and hour of cancellation