diff --git a/climateclient/utils.py b/climateclient/utils.py
index 45d7880..9371470 100644
--- a/climateclient/utils.py
+++ b/climateclient/utils.py
@@ -29,6 +29,9 @@ UUID_PATTERN = '-'.join([HEX_ELEM + '{8}', HEX_ELEM + '{4}',
                          HEX_ELEM + '{12}'])
 ELAPSED_TIME_REGEX = '^(\d+)([s|m|h|d])$'
 
+LEASE_DATE_FORMAT = '%Y-%m-%dT%H:%M:%S.%f'
+API_DATE_FORMAT = '%Y-%m-%d %H:%M'
+
 
 def env(*args, **kwargs):
     """Returns the first environment variable set.
@@ -139,9 +142,12 @@ def _find_resource_id_by_name(client, resource, name):
                                                status_code=404)
 
 
-def from_elapsed_time_to_seconds(elapsed_time):
-    """Return the amount of seconds based on the time_option parameter
-    :param: time_option: a string that matches ELAPSED_TIME_REGEX
+def from_elapsed_time_to_seconds(elapsed_time, pos_sign=True):
+    """Return the positive or negative amount of seconds based on the
+    elapsed_time parameter with a sign depending on the sign parameter.
+    :param: elapsed_time: a string that matches ELAPSED_TIME_REGEX
+    :param: sign: if pos_sign is True, the returned value will be positive.
+    Otherwise it will be positive.
     """
     is_elapsed_time = re.match(ELAPSED_TIME_REGEX, elapsed_time)
     if is_elapsed_time is None:
@@ -161,4 +167,17 @@ def from_elapsed_time_to_seconds(elapsed_time):
     }[elapsed_time_option](elapsed_time_value)
 
     # the above code returns a "float"
-    return int(seconds)
+    if pos_sign:
+        return int(seconds)
+    return int(seconds) * -1
+
+
+def from_elapsed_time_to_delta(elapsed_time, pos_sign=True):
+    """Return the positive or negative delta time based on the
+    elapsed_time parameter.
+    :param: elapsed_time: a string that matches ELAPSED_TIME_REGEX
+    :param: sign: if sign is True, the returned value will be negative.
+    Otherwise it will be positive.
+    """
+    seconds = from_elapsed_time_to_seconds(elapsed_time, pos_sign=pos_sign)
+    return datetime.timedelta(seconds=seconds)
diff --git a/climateclient/v1/leases.py b/climateclient/v1/leases.py
index 6e77f03..4ed417b 100644
--- a/climateclient/v1/leases.py
+++ b/climateclient/v1/leases.py
@@ -13,10 +13,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import datetime
-
 from climateclient import base
 from climateclient.openstack.common.gettextutils import _  # noqa
+from climateclient.openstack.common import timeutils
 from climateclient import utils
 
 
@@ -36,26 +35,30 @@ class LeaseClientManager(base.BaseClientManager):
         """
         return self._get('/leases/%s' % lease_id, 'lease')
 
-    def update(self, lease_id, name=None, prolong_for=None, reduce_by=None):
+    def update(self, lease_id, name=None, prolong_for=None, reduce_by=None,
+               defer_by=None):
         """Update attributes of the lease."""
         values = {}
         if name:
             values['name'] = name
 
-        lease_length_option = prolong_for or reduce_by
-
-        if lease_length_option:
-            seconds = utils.from_elapsed_time_to_seconds(lease_length_option)
-            seconds = seconds * (1 if prolong_for else -1)
-            delta_sec = datetime.timedelta(seconds=seconds)
+        lease_end_date_change = prolong_for or reduce_by
+        lease_start_date_change = defer_by
+        lease = None
 
+        if lease_end_date_change:
             lease = self.get(lease_id)
-            cur_end_date = datetime.datetime.strptime(lease['end_date'],
-                                                      '%Y-%m-%dT%H:%M:%S.%f')
-            new_end_date = cur_end_date + delta_sec
-            values['end_date'] = datetime.datetime.strftime(
-                new_end_date, '%Y-%m-%d %H:%M'
-            )
+            self._add_lease_date(values, lease, 'end_date',
+                                 lease_end_date_change,
+                                 prolong_for is not None)
+
+        if lease_start_date_change:
+            if lease is None:
+                lease = self.get(lease_id)
+            self._add_lease_date(values, lease, 'start_date',
+                                 lease_start_date_change,
+                                 True)
+
         if not values:
             return _('No values to update passed.')
         return self._update('/leases/%s' % lease_id, values,
@@ -71,3 +74,12 @@ class LeaseClientManager(base.BaseClientManager):
         if sort_by:
             leases = sorted(leases, key=lambda l: l[sort_by])
         return leases
+
+    def _add_lease_date(self, values, lease, key, delta_date, positive_delta):
+        delta_sec = utils.from_elapsed_time_to_delta(
+            delta_date,
+            pos_sign=positive_delta)
+        date = timeutils.parse_strtime(lease[key],
+                                       utils.LEASE_DATE_FORMAT)
+        values[key] = timeutils.strtime(date + delta_sec,
+                                        utils.API_DATE_FORMAT)
diff --git a/climateclient/v1/shell_commands/leases.py b/climateclient/v1/shell_commands/leases.py
index 2e8ec00..61fc6b5 100644
--- a/climateclient/v1/shell_commands/leases.py
+++ b/climateclient/v1/shell_commands/leases.py
@@ -250,6 +250,15 @@ class UpdateLease(command.UpdateCommand):
             help='Time to reduce lease by',
             default=None
         )
+
+        #defer-by and a 'future' advance-by are mutually exclusive
+        group = parser.add_mutually_exclusive_group()
+        group.add_argument(
+            '--defer-by',
+            help='Time to defer the lease start',
+            default=None
+        )
+
         return parser
 
     def args2body(self, parsed_args):
@@ -260,6 +269,8 @@ class UpdateLease(command.UpdateCommand):
             params['prolong_for'] = parsed_args.prolong_for
         if parsed_args.reduce_by:
             params['reduce_by'] = parsed_args.reduce_by
+        if parsed_args.defer_by:
+            params['defer_by'] = parsed_args.defer_by
         return params