After you prepare a transformation for replication or cutover operations, you might need to delete the transformation in certain conditions to abort the transformation workflow. The Delete operation takes an optional request body. Look at the API reference documentation under Transformations > DELETE > Request body > Schema to understand that the Delete operation has an optional request body.
The DELETE method returns standard operation information that you can use to track the delete operation.
Method: DELETE
https://151.155.185.143/MigrateApi/2019.5/transformations/50023e0d-91e3-4aef-b847-aa6400e4ffa2
{
"preserveSource": false,
"cleanupSource": true,
"removeTarget": true
}