diff --git a/murano/engine/system/heat_stack.py b/murano/engine/system/heat_stack.py
index f1af861f..9676dbc1 100644
--- a/murano/engine/system/heat_stack.py
+++ b/murano/engine/system/heat_stack.py
@@ -52,7 +52,7 @@ class HeatStack(object):
         self._last_stack_timestamps = (None, None)
         self._tags = ''
         self._owner = this.find_owner('io.murano.CloudRegion')
-        self._region_name = None
+        self._region_name = region_name
 
     @staticmethod
     def _create_client(session, region_name):
diff --git a/murano/engine/system/workflowclient.py b/murano/engine/system/workflowclient.py
index 9b266726..717c1e91 100644
--- a/murano/engine/system/workflowclient.py
+++ b/murano/engine/system/workflowclient.py
@@ -39,7 +39,7 @@ class MistralError(Exception):
 
 @dsl.name('io.murano.system.MistralClient')
 class MistralClient(object):
-    def __init__(self, this, region_name):
+    def __init__(self, this, region_name=None):
         self._owner = this.find_owner('io.murano.Environment')
         self._region_name = region_name