Step 1 (open screen)
From the Flightplan (FPL) menu, select the Flightplan - Overview screen.
Step 2 (search for a flightplan)
As described in Flightplan - Overview you can search here for the flightplan you want to change.
Step 3 (select a flightplan)
After the results of your previous search are displayed, select the flightplan of your choice for modification. The selected flightplan/row of the results table will be highlighted in blue. If the flightplan proposal has been accepted the several modification buttons like Cancel, Delay, and DEP/ARR Message are available, in addition to the Open button.
If the flightplan proposal has been approved all modification options are also available in the detailed Flightplan view, which can be accessed by clicking the Open button for a selected flightplan. For further information about the Flightplan (FPL), see the help.
Step 4 (change selected flightplan)
If you want to change a selected flightplan just click the Open button. The Change Flightplan screen is similar to the Create a new Flightplan screen except that some fields are read only.
On the Flightplan tab all fields can be modified except the read only ones like
(7) Aircraft ID
(8) Flight Rules
(13) Departure
(16) Destination
On the SPL tab all fields can be modified.
The other two tabs Client Data and Notifications are read only.
Step 5 (response to modified flightplan)
The receiver of your flightplan modifications will either accept or reject your change proposal as described in Flightplan - Overview.