Update/cancel event in Google Email Markup

Question

I can successfully add an event to an HTML confirmation email using the following markup:

{
"@context": "http://schema.org",
"@type": "EventReservation",
"reservationNumber": "9973180",
"reservationStatus": "http://schema.org/Confirmed",
"underName": {
    "@type": "Person",
    "name": "John Smith"
},
"reservationFor": {
    "@type": "Event",
    "name": "Test Event"
},
"startDate": "2018-04-19T11:30:00+03:00",
"endDate": "2018-04-19T12:30:00+03:00",
"location": {
    "@type": "Place",
    "name": "",
    "address": {
        "@type": "PostalAddress",
        "streetAddress": "347 West 55th St",
        "addressLocality": "New York",
        "addressRegion": "NY",
        "postalCode": "10019",
        "addressCountry": "US"
    }
}
}

However, I am unable to:

1. Update the event by sending the same markup with a different startDate and a modifiedTime

2. Cancel the event by sending the same markup with reservationStatus = http://schema.org/Cancelled and a modifiedTime