Lease Mistake - Omits 2-year Option - Divide County, ND

I found that my lease had omitted a 2 year option. I was not sure. This lease included some extraneous material about an option which seemed to be surface rights, so I called landman. Yep, it had been forgotten. I wonder if they would have found it before the 45 day sight draft is paid to me. Anyway this was a moral obligation on my part to disclose this mistake. Northwest Divide County, North Dakota.