SSRS 2017 Subscription Rest error

Question

I have PowerShell script to update Report subscriptions en masse. I'm trying to use the PATCH method. (https://app.swaggerhub.com/apis/microsoft-rs/SSRS/2.0#/Subscriptions/UpdateSubscription)
However I'm getting a HTTP 405 Method Not Allowed. What am I doing wrong?

Here is the Rest URL example:

$uri = 'http://localhost/reportserver/reports/api/v2.0/Subscriptions(f6b3ff9a-9844-4d11-a61b-d2bfc02c84f4)'
Invoke-RestMethod -Uri $uri -UseDefaultCredentials -ContentType 'application/json' -Method Patch -Body $Body

Here is the JSON Body:
{
"Id": "f6b3ff9a-9844-4d11-a61b-d2bfc02c84f4",
"ExtensionSettings": {
"ParameterValues": {
"Name": "pRegion",
"Value": "Atlantic",
"IsValueFieldReference": false
}
}
}

Answer 1

I figured it out.
First, the URL should be: http://localhost/reports/api/v2.0/Subscriptions(f6b3ff9a-9844-4d11-a61b-d2bfc02c84f4)

Second, the body should be:

{
"Id": "96ad5f4e-da19-41a2-8fed-9929105b37a8",
"ParameterValues": [
{
"Name": "pRegion",
"Value": "Atlantic",
"IsValueFieldReference": true
}
]
}