HTTP post to a form to clear a contact property

[MNorlander]

We need to know what we are doing wrong when posting to an HubSpot form trying to clear a contact property.
Can someone explain to us how a property that shall be cleared should look like in the format “Content Type: application/x-www-form-urlencoded”.

We are trying to post the following values to clear the property named “LicenseExpirationDate”

Value: null
email=mattias.norlander%40atollic.com&firstname=Mattias&LicenseExpirationDate&lastname=Norlander

Value: "null"
email=mattias.norlander%40atollic.com&firstname=Mattias&LicenseExpirationDate=null&lastname=Norlander

Value: ""
email=mattias.norlander%40atollic.com&firstname=Mattias&LicenseExpirationDate=&lastname=Norlander

What value are we supposed to post? the above examples does not appear to work.

[3PETE]

@Norlander You can use this endpoint here to update a contact property.

developers.hubspot.com

Create or update a contact

POST /contacts/v1/contact/createOrUpdate/email/:contact_email - Create a contact if it doesn't exist in a portal already, or update it with the latest property values if it does.