A more thorough explanation:

An assignment clause, also known as a change-of-ownership clause, is a provision in an oil-and-gas lease that outlines the notice requirements for a lessee when there is a change in ownership of the leased land. This clause specifies the obligations of the lessee to recognize the new owner and continue the lease agreement.

For example, if a company leases land for oil and gas exploration, the assignment clause in the lease agreement would specify that the lessee must be notified in writing of any change in ownership of the land. The lessee would then have a certain amount of time to recognize the new owner and continue the lease agreement.

Another example would be if the original landowner sells the land to a new owner, the assignment clause would require the new owner to provide written notice to the lessee of the change in ownership. The lessee would then have to recognize the new owner and continue the lease agreement.

These examples illustrate how an assignment clause protects the interests of both the lessee and the landowner by ensuring that any change in ownership is properly communicated and recognized in the lease agreement.