diff --git a/app/orm.py b/app/orm.py
index 50ff3ce..bbabbbc 100644
--- a/app/orm.py
+++ b/app/orm.py
@@ -1,4 +1,5 @@
-import datetime
+from datetime import datetime, timedelta
+from dateutil.relativedelta import relativedelta
 
 from sqlalchemy import Column, VARCHAR, CHAR, ForeignKey, DATETIME, update, and_, inspect
 from sqlalchemy.ext.declarative import declarative_base
@@ -81,7 +82,10 @@ class Lease(Base):
     def __repr__(self):
         return f'Lease(origin_ref={self.origin_ref}, lease_ref={self.lease_ref}, expires={self.lease_expires})'
 
-    def serialize(self, renewal_period: float, renewal_delta: datetime.timedelta) -> dict:
+    def serialize(self, renewal_period: float, renewal_delta: timedelta) -> dict:
+        lease_renewal = int(Lease.calculate_renewal(renewal_period, renewal_delta).total_seconds())
+        lease_renewal = self.lease_created + relativedelta(seconds=lease_renewal)
+
         return {
             'lease_ref': self.lease_ref,
             'origin_ref': self.origin_ref,
@@ -89,7 +93,7 @@ class Lease(Base):
             'lease_created': self.lease_created.isoformat(),
             'lease_expires': self.lease_expires.isoformat(),
             'lease_updated': self.lease_updated.isoformat(),
-            'lease_renewal': Lease.calculate_renewal(renewal_period, renewal_delta),
+            'lease_renewal': lease_renewal.isoformat(),
         }
 
     @staticmethod
@@ -134,7 +138,7 @@ class Lease(Base):
         return entity
 
     @staticmethod
-    def renew(engine: Engine, lease: "Lease", lease_expires: datetime.datetime, lease_updated: datetime.datetime):
+    def renew(engine: Engine, lease: "Lease", lease_expires: datetime, lease_updated: datetime):
         session = sessionmaker(bind=engine)()
         x = dict(lease_expires=lease_expires, lease_updated=lease_updated)
         session.execute(update(Lease).where(and_(Lease.origin_ref == lease.origin_ref, Lease.lease_ref == lease.lease_ref)).values(**x))
@@ -158,16 +162,17 @@ class Lease(Base):
         return deletions
 
     @staticmethod
-    def calculate_renewal(renewal_period: float, delta: datetime.timedelta):
+    def calculate_renewal(renewal_period: float, delta: timedelta) -> timedelta:
         """
+        import datetime
         LEASE_RENEWAL_PERIOD=0.2  # 20%
         delta = datetime.timedelta(days=1)
         renew = delta.total_seconds() * LEASE_RENEWAL_PERIOD
-        renew = timedelta(seconds=renew)
+        renew = datetime.timedelta(seconds=renew)
         expires = delta - renew  # 19.2
         """
         renew = delta.total_seconds() * renewal_period
-        renew = datetime.timedelta(seconds=renew)
+        renew = timedelta(seconds=renew)
         return delta - renew