43 CFR §3140.41

1. (a)The owner of an oil and gas lease, or the owner of a valid claim based on a mineral location will have such lease or claim converted to a combined hydrocarbon lease when the plan of operations, filed under § 3140.23, is deemed acceptable and is approved by the authorized officer.
2. (b)The conversion of a lease within a unit of the National Park System will be approved only with the consent of the Regional Director of the National Park Service in accordance with § 3140.70.
3. (c)A plan of operations may not be approved in part but may be approved where it contains an appropriately staged plan of exploration and development operations.