Update use-case6.md - editorial updates.

    * discovers that Application Mobility Service (AMS) is available

    * discover other services

    * _See [related scenario](./macro-network.md#macro-network-4g-5g-wifi-dual-mec-platforms) for details_

  * MEC Applications:

  * MEC Applications (context transfer preparation):

    * register & subscribe to AMS

    * reports user terminals to AMS

    * locally creates a context for each terminal

  * AMS:

    * detects the need for context transfer

    * notifies the source MEC application with the target context transfer endpoint

  *MEC Application:

  * MEC Applications (context transfer execution):

    * Performs the context transfer

    * Informs AMS of context transfer completion

| 7. `POST .../subscriptions` | MEC Applications subscribe for AMS notifications |

| 8. `PUT .../app_mobility_services/{appMobilityServiceId}` | Optional step if no device was reported in step 6 <br><br> MEC Applications can include device information (e.g. which device is using the application); devices must be devices present in the scenario and can be provisioned in the MEC Application or discovered by the MEC Application via the Location service. |

| 9. As the terminal moves through the network | AMS detects if context transfer is needed. <br><br> AMS issues a Mobility Procedure Notification to the MEC Application instance used by the terminal of the target endpoint to perform the context transfer. |

| 10. MEC Application performs the context transfer to the target MEC Application instance | Transfer happens on user premises. <br><br> Transfer is out of scope of the MEC Sandbox |

| 10. MEC Application performs the context transfer to the target MEC Application instance | Transfer executes within the Sandbox user's external environment.  The context transfer is out of scope of the MEC Sandbox and AMS. |

| 11. `PUT .../app_mobility_services/{appMobilityServiceId}` | MEC Applications informs AMS that the context transfer is complete <br><br> The device is now reported as using the target MEC Application and removed from the source MEC Application |

| 12. Stop MEC Application | |

| 13. Terminate scenario | |