**To modify a transit gateway** The following ``modify-transit-gateway`` example modifies the specified transit gateway by enabling ECMP support for VPN attachments. :: aws ec2 modify-transit-gateway \ --transit-gateway-id tgw-111111222222aaaaa \ --options VpnEcmpSupport=enable Output:: { "TransitGateway": { "TransitGatewayId": "tgw-111111222222aaaaa", "TransitGatewayArn": "64512", "State": "modifying", "OwnerId": "123456789012", "CreationTime": "2020-04-30T08:41:37.000Z", "Options": { "AmazonSideAsn": 64512, "AutoAcceptSharedAttachments": "disable", "DefaultRouteTableAssociation": "enable", "AssociationDefaultRouteTableId": "tgw-rtb-0123456789abcd123", "DefaultRouteTablePropagation": "enable", "PropagationDefaultRouteTableId": "tgw-rtb-0123456789abcd123", "VpnEcmpSupport": "enable", "DnsSupport": "enable" } } } For more information, see `Transit gateways <https://docs.aws.amazon.com/vpc/latest/tgw/tgw-transit-gateways.html>`__ in the *Transit Gateways Guide*.