Alterations Tenant shall make no changes in or to the demised premises of any nature without Owner's prior written consent. Subject to the prior written consent of Owner, and to the provisions of this article, Tenant at Tenant's expense, may make alterations, installations, additions or improvements which are non-structural and which do not affect utility services or plumbing and electrical lines, in or to the interior of the demised premises by using contractors or mechanics first approved by Owner. Tenant shall, before making any alterations, additions, installations or improvements, at its expense, obtain all permits, approvals and certificates required by any governmental or quasi-governmental bodies and (upon completion) certificates of final approval thereof and shall deliver promptly duplicates of all such permits, approvals and certificates to Owner and Tenant agrees to carry and will cause Tenant's contractors and sub-contractors to carry such xxxxxxx'x compensation, general liability, personal and property damage insurance as Owner may require. If any mechanic's lien is filed against the demised premises, or the building of which the same forms a part, for work claimed to have been done for, or materials furnished to, Tenant, whether or not done pursuant to this article, the same shall be discharged by Tenant within thirty days thereafter, at Tenant's expense, by filing the bond required by law. All fixtures and all paneling, partitions, railings and like installations, installed in the premises at any time, either by Tenant or by Owner in Tenant's behalf, shall, upon installation, become the property of Owner and shall remain upon and be surrendered with the demised premises unless Owner, by notice to Tenant no later than twenty days prior to the date fixed as the termination of this lease, elects to relinquish Owner's right thereto and to have them removed by Tenant, in which event the same shall be removed from the premises by Tenant prior to the expiration of the lease, at Tenant's expense. Nothing in this Article shall be construed to give Owner title to or to prevent Tenant's removal of trade fixtures, moveable office furniture and equipment, but upon removal of any such from the premises or upon removal of other installations as may be required by Owner, Tenant shall immediately and at its expense, repair and restore the premises to the condition existing prior to installation and repair any damage to the demised premises or the building due to such removal. All property permitted or required to be removed, by Tenant at the end of the term remaining in the premises after Tenant's removal shall be deemed abandoned and may, at the election of Owner, either be retained as Owner's property or may be removed from the premises by Owner, at Tenant's expense.