Modifies the options for a VPN tunnel in an Amazon Web Services Site-to-Site VPN connection. You can modify multiple options for a tunnel in a single request, but you can only modify one tunnel at a time. For more information, see <a href="https://docs.aws.amazon.com/vpn/latest/s2svpn/VPNTunnels.html">Site-to-Site VPN tunnel options for your Site-to-Site VPN connection</a> in the <i>Amazon Web Services Site-to-Site VPN User Guide</i>.