The memorandum concept is the stupidest thing ever created in the oil and gas business. In prospect development I have found many times where a copy of an old lease simply does not exist. There is vital information in the lease that needs to be of record, such as Pugh clauses and depth severances. If these are not of record and a copy of the lease is not available then there can be an unknown that can’t be solved. Focus on editing the memo as well as the lease if you are going to execute one.