If I have a running lease, can I have a particular condition of lease changed?

No, you cannot change any conditions of the lease unless the contractual conditions themselves provide for such alteration. In terms of the Disposal of Government Land Act altering a condition of lease is tantamount to a new disposal and therefore falls to be considered under the disposal procedures contemplated in the law. Normally this would mean re-issuing the property on tender or otherwise seeking the approval of the House of Representatives via a special resolution.