1**To modify a transit gateway VPC attachment**
2
3The following ``modify-transit-gateway-vpc-attachment`` example adds a subnet to the specified transit gateway VPC attachment. ::
4
5    aws ec2 modify-transit-gateway-vpc-attachment \
6        --transit-gateway-attachment-id tgw-attach-09fbd47ddfEXAMPLE \
7        --add-subnet-ids subnet-0e51f45802EXAMPLE
8
9Output::
10
11    {
12        "TransitGatewayVpcAttachment": {
13            "TransitGatewayAttachmentId": "tgw-attach-09fbd47ddfEXAMPLE",
14            "TransitGatewayId": "tgw-0560315ccfEXAMPLE",
15            "VpcId": "vpc-5eccc927",
16            "VpcOwnerId": "111122223333",
17            "State": "modifying",
18            "SubnetIds": [
19                "subnet-0e51f45802EXAMPLE",
20                "subnet-1EXAMPLE"
21            ],
22            "CreationTime": "2019-08-08T16:47:38.000Z",
23            "Options": {
24                "DnsSupport": "enable",
25                "Ipv6Support": "disable"
26            }
27        }
28    }
29
30For more information, see `Transit Gateway Attachments to a VPC <https://docs.aws.amazon.com/vpc/latest/tgw/tgw-vpc-attachments.html>`__ in the *AWS Transit Gateways Guide*.
31