diff --git a/specification/reservations/resource-manager/Microsoft.Capacity/preview/2019-04-01/reservations.json b/specification/reservations/resource-manager/Microsoft.Capacity/preview/2019-04-01/reservations.json
index 7e369f3d7375..0fe540dab94d 100644
--- a/specification/reservations/resource-manager/Microsoft.Capacity/preview/2019-04-01/reservations.json
+++ b/specification/reservations/resource-manager/Microsoft.Capacity/preview/2019-04-01/reservations.json
@@ -1132,7 +1132,7 @@
     "InstanceFlexibility" : {
       "type" : "string",
       "description" : "Turning this on will apply the reservation discount to other VMs in the same VM size group. Only specify for VirtualMachines reserved resource type.",
-      "enum" : [ true, false ],
+      "enum" : [ "On", "Off" ],
       "x-ms-enum" : {
         "name" : "InstanceFlexibility",
         "modelAsString" : true