I have a requirement to conditionally tag resources based on user response to the downtime parameter and the value of environment defined in map. This tag is later used by the lambda function to turn off the instances at night. 

I tried it like this with no luck - 

Conditions - 

```
    "EnvCheck": {
        "Fn::Not": [
            {"Fn::Equals": [{"Ref": "EnvironmentType"}, "prod"]}
        ]
    },
    "EnableDowntimeTag": {
        "Fn::And": [
            {"Fn::Equals": [{"Ref": "CustodianDowntime"}, "true"]},
            {"Condition": "EnvCheck"}
        ]
    }

```

Tags section

```
    "Tags": [
                {
                    "Key": "OwnerContact",
                    "PropagateAtLaunch": "true",
                    "Value": {
                        "Ref": "OwnerContact"
                    }
                },
                {
                    "Condition" : "EnableDowntimeTag",
                    "Key": "custodian_downtime",
                    "PropagateAtLaunch": "true",
                    "Value": "Offhours tz=ET"
                }
            ],

```

Any idea on how to add a conditional tag?

Thanks!