diff --git a/specification/reservations/resource-manager/Microsoft.Capacity/preview/2020-10-01-preview/examples/ChangeDirectoryReservationOrder.json b/specification/reservations/resource-manager/Microsoft.Capacity/preview/2020-10-01-preview/examples/ChangeDirectoryReservationOrder.json
new file mode 100644
index 000000000000..e31627c889dc
--- /dev/null
+++ b/specification/reservations/resource-manager/Microsoft.Capacity/preview/2020-10-01-preview/examples/ChangeDirectoryReservationOrder.json
@@ -0,0 +1,29 @@
+{
+  "parameters": {
+    "api-version": "2020-10-01-preview",
+    "reservationOrderId": "a075419f-44cc-497f-b68a-14ee811d48b9",
+    "body": {
+      "destinationTenantId": "906655ea-30be-4587-9d12-b50e077b0f32"
+    }
+  },
+  "responses": {
+    "200": {
+      "body": {
+        "reservationOrder" : {
+          "id": "1f14354c-dc12-4c8d-8090-6f295a3a34aa",
+          "name": "VM_RI_10-02-2020_15-21",
+          "isSucceeded": true,
+          "error": "error string"
+        },
+        "reservations" : [
+          {
+            "id": "1f14354c-dc12-4c8d-8090-6f295a3a34aa",
+            "name": "VM_RI_10-02-2020_15-21",
+            "isSucceeded": true,
+            "error": "error string"
+          }
+        ]
+      }
+    }
+  }
+}
diff --git a/specification/reservations/resource-manager/Microsoft.Capacity/preview/2020-10-01-preview/reservations.json b/specification/reservations/resource-manager/Microsoft.Capacity/preview/2020-10-01-preview/reservations.json
index 65ffe539d6a2..2cf222b5ddf8 100644
--- a/specification/reservations/resource-manager/Microsoft.Capacity/preview/2020-10-01-preview/reservations.json
+++ b/specification/reservations/resource-manager/Microsoft.Capacity/preview/2020-10-01-preview/reservations.json
@@ -322,6 +322,49 @@
         }
       }
     },
+    "/providers/Microsoft.Capacity/reservationOrders/{reservationOrderId}/changeDirectory": {
+      "post": {
+        "summary": "Change direcotory of `ReservationOrder`.",
+        "description": "Change directory (tenant) of `ReservationOrder` and all `Reservation` under it to specified tenant id",
+        "operationId": "ReservationOrder_ChangeDirectory",
+        "x-ms-examples": {
+          "Split": {
+            "$ref": "./examples/ChangeDirectoryReservationOrder.json"
+          }
+        },
+        "parameters": [
+          {
+            "$ref": "#/parameters/ReservationOrderIdParameter"
+          },
+          {
+            "$ref": "#/parameters/ApiVersionParameter"
+          },
+          {
+            "$ref": "#/parameters/ChangeDirectoryParameter"
+          }
+        ],
+        "tags": [
+          "ReservationOrder, ChangeDirectory"
+        ],
+        "responses": {
+          "200": {
+            "description": "List of `Reservation`s created after the split operation.",
+            "schema": {
+              "type": "array",
+              "items": {
+                "$ref": "#/definitions/ChangeDirectoryResponse"
+              }
+            }
+          },
+          "default": {
+            "description": "Unexpected error",
+            "schema": {
+              "$ref": "#/definitions/Error"
+            }
+          }
+        }
+      }
+    },
     "/providers/Microsoft.Capacity/reservationOrders/{reservationOrderId}/split": {
       "post": {
         "summary": "Split the `Reservation`.",
@@ -1482,6 +1525,59 @@
         }
       }
     },
+    "ChangeDirectoryResponse": {
+      "type": "object",
+      "description": "Change direcotry response",
+      "properties": {
+        "reservationOrder": {
+          "type": "object",
+          "description": "Change direcotry result for reservation order",
+          "properties": {
+            "id": {
+              "type": "string",
+              "description": "Identifier of the reservation order"
+            },
+            "name": {
+              "type": "string",
+              "description": "Name of the reservation order"
+            },
+            "isSucceeded": {
+              "description": "True if change directory operation succeeded on this reservation order",
+              "type": "boolean"
+            },
+            "error": {
+              "type": "string",
+              "description": "Error reason if operation failed. Null otherwise"
+            }
+          }
+        },
+        "reservations": {
+          "type": "array",
+          "items": {
+            "type": "object",
+            "description": "Change direcotry result for reservation",
+            "properties": {
+              "id": {
+                "type": "string",
+                "description": "Identifier of the reservation"
+              },
+              "name": {
+                "type": "string",
+                "description": "Name of the reservation"
+              },
+              "isSucceeded": {
+                "description": "True if change directory operation succeeded on this reservation",
+                "type": "boolean"
+              },
+              "error": {
+                "type": "string",
+                "description": "Error reason if operation failed. Null otherwise"
+              }
+            }
+          }
+        }
+      }
+    },
     "RenewPropertiesResponse": {
       "type": "object",
       "properties": {
@@ -1829,6 +1925,15 @@
         }
       }
     },
+    "ChangeDirectoryRequest": {
+      "type": "object",
+      "properties": {
+        "destinationTenantId": {
+          "description": "Tenant id GUID that reservation order is to be tranferred to",
+          "type": "string"
+        }
+      }
+    },
     "Error": {
       "type": "object",
       "properties": {
@@ -2183,6 +2288,16 @@
         "$ref": "#/definitions/SplitRequest"
       }
     },
+    "ChangeDirectoryParameter": {
+      "name": "body",
+      "x-ms-parameter-location": "method",
+      "in": "body",
+      "required": true,
+      "description": "Information needed to change directory of reservation order",
+      "schema": {
+        "$ref": "#/definitions/ChangeDirectoryRequest"
+      }
+    },
     "ApiVersionParameter": {
       "name": "api-version",
       "in": "query",