At present, there is not a way to 'uninvite' yourself from a conference call you were invited to by another organizer or host. However, we will be adding this feature in the near future.
For now, there is a workaround that we can suggest. You can easily set up a filter or rule within your email account to have those messages sent directly to a specific folder, archived or deleted. We have instruction links below for Gmail and Outlook. If you have another email provider and would like help with that, just reach out to our support team for assistance.
Create rules to filter your emails - Gmail Help - Google Support
Manage email messages by using rules - Outlook - Office Support