diff --git a/backend/src/main/resources/db/migration/V3__nullable_appointment_petid.sql b/backend/src/main/resources/db/migration/V3__nullable_appointment_petid.sql
new file mode 100644
index 00000000..06639401
--- /dev/null
+++ b/backend/src/main/resources/db/migration/V3__nullable_appointment_petid.sql
@@ -0,0 +1,3 @@
+ALTER TABLE appointment MODIFY petId BIGINT NULL;
+ALTER TABLE appointment DROP FOREIGN KEY fk_appointment_pet;
+ALTER TABLE appointment ADD CONSTRAINT fk_appointment_pet FOREIGN KEY (petId) REFERENCES pet(petId) ON DELETE SET NULL;