Update MigrationGuide.md (Azure#21738)

Clarified what the sample demonstrates

Author: lilyjma

sdk/servicebus/Azure.Messaging.ServiceBus/MigrationGuide.md

@@ -103,7 +103,7 @@ ServiceBusClient client = new ServiceBusClient(connectionString);
 
 #### Administration client
 
-This replaces the `ManagementClient` from `Microsoft.Azure.ServiceBus`. For example usage please see the sample for [creating a subscription with a connection string](https://github.com/Azure/azure-sdk-for-net/blob/master/sdk/servicebus/Azure.Messaging.ServiceBus/samples/Sample07_CrudOperations.md).
+The `ServiceBusAdministrationClient` replaces the `ManagementClient` from `Microsoft.Azure.ServiceBus`. For example usage please see the sample for [CRUD operations using the `ServiceBusAdministrationClient`](https://github.com/Azure/azure-sdk-for-net/blob/master/sdk/servicebus/Azure.Messaging.ServiceBus/samples/Sample07_CrudOperations.md).
 
 
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