diff --git a/app/dao/jobs_dao.py b/app/dao/jobs_dao.py
index c40311d16..ef35206f5 100644
--- a/app/dao/jobs_dao.py
+++ b/app/dao/jobs_dao.py
@@ -9,7 +9,6 @@ from sqlalchemy import (
     desc,
     func,
 )
-from sqlalchemy.testing import not_in_
 
 from app import db
 from app.dao.dao_utils import transactional
@@ -27,7 +26,6 @@ from app.models import (
     NOTIFICATION_CANCELLED,
     JOB_STATUS_CANCELLED
 )
-from app.variables import LETTER_TEST_API_FILENAME
 
 
 @statsd(namespace="dao")
@@ -156,36 +154,31 @@ def dao_get_jobs_older_than_data_retention(notification_types):
 
 
 @transactional
-def dao_cancel_letter_job(service_id, job_id):
-    if can_cancel_letter_job(job_id, service_id):
+def dao_cancel_letter_job(job):
+    if can_cancel_letter_job(job):
         number_of_notifications_cancelled = Notification.query.filter(
-            Notification.job_id == job_id
+            Notification.job_id == job.id
         ).update({'status': NOTIFICATION_CANCELLED,
                   'updated_at': datetime.utcnow(),
                   'billable_units': 0})
-        # calling this 2x - pass job into can_cancel_letter_job
-        job = dao_get_job_by_service_id_and_job_id(service_id, job_id)
         job.job_status = JOB_STATUS_CANCELLED
         dao_update_job(job)
         return number_of_notifications_cancelled
+    else:
+        return False
 
 
-def can_cancel_letter_job(job_id, service_id):
-    job = dao_get_job_by_service_id_and_job_id(service_id, job_id)
+def can_cancel_letter_job(job):
     # assert is a letter job
     # assert job status == finished???
     # Notifications are not in pending-virus-check
-    count_notifications_in_sending = Notification.query.filter(
-        Notification.job_id == job_id,
-        Notification.status.not_in_('created', 'pending-virus-check', 'cancelled')
+    count_notifications = Notification.query.filter(
+        Notification.job_id == job.id,
+        Notification.status.in_(['created', 'pending-virus-check', 'cancelled'])
     ).count()
-    if count_notifications_in_sending > 0:
+    if count_notifications != job.notification_count:
         return False
-    if not letter_can_be_cancelled(NOTIFICATION_CREATED, job.created_at):
-        return False
-    else:
-        return True
-
+    return letter_can_be_cancelled(NOTIFICATION_CREATED, job.created_at)
 
 
 
diff --git a/app/job/rest.py b/app/job/rest.py
index 1d125c007..9123a59da 100644
--- a/app/job/rest.py
+++ b/app/job/rest.py
@@ -5,7 +5,6 @@ from flask import (
     request,
     current_app
 )
-from notifications_utils.letter_timings import letter_can_be_cancelled
 
 from app.aws.s3 import get_job_metadata_from_s3
 from app.dao.jobs_dao import (
@@ -14,7 +13,9 @@ from app.dao.jobs_dao import (
     dao_get_job_by_service_id_and_job_id,
     dao_get_jobs_by_service_id,
     dao_get_future_scheduled_job_by_id_and_service_id,
-    dao_get_notification_outcomes_for_job, dao_cancel_letter_job
+    dao_get_notification_outcomes_for_job,
+    dao_cancel_letter_job,
+    can_cancel_letter_job
 )
 from app.dao.fact_notification_status_dao import fetch_notification_statuses_for_job
 from app.dao.services_dao import dao_fetch_service_by_id
@@ -62,6 +63,19 @@ def cancel_job(service_id, job_id):
     return get_job_by_service_and_job_id(service_id, job_id)
 
 
+@job_blueprint.route('/<job_id>/cancel-letter-job')
+def cancel_letter_job(service_id, job_id):
+    job = dao_get_job_by_service_id_and_job_id(service_id, job_id)
+    if can_cancel_letter_job(job):
+        dao_cancel_letter_job(job)
+        return jsonify(), 201
+    else:
+        # reasons the letter can't be cancelled:
+        # letters are not yet saved to db  --> can still cancel but later
+        # it's too late
+        return jsonify("CHANGE ME: some error to say the job can't be cancelled"), 400
+
+
 @job_blueprint.route('/<job_id>/notifications', methods=['GET'])
 def get_all_notifications_for_service_job(service_id, job_id):
     data = notifications_filter_schema.load(request.args).data
diff --git a/tests/app/dao/test_jobs_dao.py b/tests/app/dao/test_jobs_dao.py
index 500bd90f0..731ae959a 100644
--- a/tests/app/dao/test_jobs_dao.py
+++ b/tests/app/dao/test_jobs_dao.py
@@ -311,15 +311,24 @@ def assert_job_stat(job, result, sent, delivered, failed):
     assert result.failed == failed
 
 
-def test_dao_cancel_letter_job_does_not_allow_cancel_if_notification_in_sending(sample_job):
-    create_notification(template=sample_job.template, job=sample_job, status='sending')
-    create_notification(template=sample_job.template, job=sample_job, status='created')
-    assert not dao_cancel_letter_job(service_id=sample_job.service_id, job_id=sample_job.id)
+def test_dao_cancel_letter_job_does_not_allow_cancel_if_notification_in_sending(sample_letter_template):
+    job = create_job(template=sample_letter_template, notification_count=2)
+    create_notification(template=job.template, job=job, status='sending')
+    create_notification(template=job.template, job=job, status='created')
+    assert not dao_cancel_letter_job(job)
 
 
 def test_dao_cancel_letter_job_updates_notifications_and_job_to_cancelled(sample_job):
     notification = create_notification(template=sample_job.template, job=sample_job, status='created')
-    assert dao_cancel_letter_job(service_id=sample_job.service_id, job_id=sample_job.id) == 1
+    assert dao_cancel_letter_job(sample_job) == 1
     assert notification.status == 'cancelled'
     assert sample_job.job_status == 'cancelled'
 
+
+def test_dao_cancel_letter_job_returns_false_if_too_late():
+    pass
+
+
+def test_dao_cancel_letter_returns_false_if_not_a_letter_job():
+    pass
+