K.S.A. 58-30a10

If additional compensation is owed to a broker as a result of the exercise of an option to expand the leased premises, the renewal or extension of a lease, the purchase of the property or other transaction pursuant to a written agreement signed by the current owner or tenant, the broker may record its notice of lien at any time after execution of the lease or other written agreement containing such option but not later than 90 days after the occurrence of the transaction for which the additional commission is claimed.