MHDS Specification 4 defines the Cancellation object.
| Attribute | Data Type | Description |
| CANCELLATION | String | Random alphanumeric ID; imported cancellations’ IDs might be numeric |
| STAMP | String or Datetime | Date & time of booking |
| DURATION | Int | Number of minutes |
| USER | String | Therapist ID (references User object) |
| OFFICE | String | Office ID |
| CLIENT | String | Client ID of primary client; invoice will be issued to this client |
| CLIENTS | String | Comma-delimited list of Client IDs |
| INVOICE | String | Invoice ID |
| SUPERVISOR | String | Therapist ID of supervisor (if applicable) |
| NOTES | String | See S10.6 |
| ITEMS | String | Comma-delimited list of Item IDs |
| ARRIVED | String or Int | 1 = arrived; 0 = not arrived |
| ONLINE | String or Int | See S10.3 |
| IMPORTED | String or Int | See S10.1 & S10.2 |