Or you can use an alternate way, where in you can manually insert the attribute into your html coding.
If you have cancellation object in your Incident Management.
Suppose On Incident module Cancellation details you need to capture.
Step1 : Go to window manager - Incident Management
Step2: Go to Cancellation window, note down the field which you want to view in your notification.
Step3: The manual attribute which you can add to html code will be something like below.
<td>{_CancellationCol/_Details}</td>