diff --git a/heat/engine/environment.py b/heat/engine/environment.py
index 9ef0bbd940..0a7818e478 100644
--- a/heat/engine/environment.py
+++ b/heat/engine/environment.py
@@ -367,11 +367,15 @@ class Environment(object):
         self.registry.load(env_snippet.get(env_fmt.RESOURCE_REGISTRY, {}))
         self.params.update(env_snippet.get(env_fmt.PARAMETERS, {}))
 
-    def patch_previous_parameters(self, previous_env):
+    def patch_previous_parameters(self, previous_env, clear_parameters=[]):
         """This instance of Environment is the new environment where
         we are reusing as default the previous parameter values.
         """
         previous_parameters = copy.deepcopy(previous_env.params)
+        # clear the parameters from the previous set as requested
+        for p in clear_parameters:
+            previous_parameters.pop(p, None)
+
         # patch the new set of parameters
         previous_parameters.update(self.params)
         self.params = previous_parameters
diff --git a/heat/engine/service.py b/heat/engine/service.py
index 90aaa69e90..c0e8e0050f 100644
--- a/heat/engine/service.py
+++ b/heat/engine/service.py
@@ -658,7 +658,9 @@ class EngineService(service.Service):
                                  current_stack.disable_rollback)
         env = environment.Environment(params)
         if args.get(rpc_api.PARAM_EXISTING, None):
-            env.patch_previous_parameters(current_stack.env)
+            env.patch_previous_parameters(
+                current_stack.env,
+                args.get(rpc_api.PARAM_CLEAR_PARAMETERS, []))
         updated_stack = parser.Stack(cnxt, stack_name, tmpl,
                                      env, **common_params)
         updated_stack.parameters.set_stack_id(current_stack.identifier())
diff --git a/heat/rpc/api.py b/heat/rpc/api.py
index fe5a6ee550..c6744169a5 100644
--- a/heat/rpc/api.py
+++ b/heat/rpc/api.py
@@ -15,10 +15,12 @@ ENGINE_TOPIC = 'engine'
 
 PARAM_KEYS = (
     PARAM_TIMEOUT, PARAM_DISABLE_ROLLBACK, PARAM_ADOPT_STACK_DATA,
-    PARAM_SHOW_DELETED, PARAM_SHOW_NESTED, PARAM_EXISTING
+    PARAM_SHOW_DELETED, PARAM_SHOW_NESTED, PARAM_EXISTING,
+    PARAM_CLEAR_PARAMETERS
 ) = (
     'timeout_mins', 'disable_rollback', 'adopt_stack_data',
-    'show_deleted', 'show_nested', 'existing'
+    'show_deleted', 'show_nested', 'existing',
+    'clear_parameters'
 )
 
 STACK_KEYS = (
diff --git a/heat/tests/test_environment.py b/heat/tests/test_environment.py
index 62febfff7c..edd5b6d605 100644
--- a/heat/tests/test_environment.py
+++ b/heat/tests/test_environment.py
@@ -73,6 +73,33 @@ class EnvironmentTest(common.HeatTestCase):
         env.patch_previous_parameters(prev_env)
         self.assertEqual(expected, env.user_env_as_dict())
 
+    def test_patch_and_clear_existing_parameters(self):
+        # This tests patching cli parameters over the existing parameters
+        prev_params = {'foo': 'bar', 'tester': 'Yes',
+                       'another_tester': 'Yes'}
+        params = {'tester': 'patched'}
+        expected = {'parameters': {'foo': 'bar', 'tester': 'patched'},
+                    'resource_registry': {'resources': {}}}
+        prev_env = environment.Environment(
+            {'parameters': prev_params,
+             'resource_registry': {'resources': {}}})
+        env = environment.Environment(params)
+        env.patch_previous_parameters(prev_env, ['another_tester'])
+        self.assertEqual(expected, env.user_env_as_dict())
+
+    def test_clear_existing_parameters(self):
+        # This tests removing some parameters in the existing set of parameters
+        prev_params = {'foo': 'bar', 'tester': 'Yes'}
+        params = {}
+        expected = {'parameters': {'foo': 'bar'},
+                    'resource_registry': {'resources': {}}}
+        prev_env = environment.Environment(
+            {'parameters': prev_params,
+             'resource_registry': {'resources': {}}})
+        env = environment.Environment(params)
+        env.patch_previous_parameters(prev_env, ['tester'])
+        self.assertEqual(expected, env.user_env_as_dict())
+
     def test_global_registry(self):
         self.g_env.register_class('CloudX::Nova::Server',
                                   generic_resource.GenericResource)