This endorsement modifies such insurance as is afforded by the underlying policy or policies relating to the following designated insurance:

In consideration of the premium charged, it is understood and agreed that in the event of reduction or exhaustion of the aggregate limit or limits designated in the underlying policy or policies solely by payment of losses in respect to occurrence during the period of such underlying policy or policies, it is understood and agreed that such insurance as is afforded by this policy shall apply in excess of the reduced underlying limit or, if such limit is exhausted, shall apply as underlying insurance. But nothing contained in this endorsement shall be construed to provide insurance of occurrences which do not take place during the period this policy is in effect.

This endorsement forms a part of and is for attachment to the following described policy issued by the CNA INSURANCE company designated therein. Takes effect on the effective date of said policy, unless another effective date is shown below, at the hour stated in said policy and expires concurrently with said policy.