You can try to go to your config directory, in my case (Steam installation) it’s under
C:\Users[MyProfile]\AppData\Roaming\Microsoft Flight Simulator
This has a subdirectory MISSIONS\ACTIVITIES where you find the missions you started at least once.
Next, got into the subdirectory for the corresponding mission. There are several further subdirectories, depending on your progress. The relevant one is always the one without any _0001, _0002… at the end. Go into this subdirectory to find a .flt file wich contains the settings for the next leg. There is a block [DateTimeSeason] where you can edit “Hours” and other entries.
Taking the (payware) Okavanga Addon as an example, the proper file is under
C:\Users[MyProfile]\AppData\Roaming\Microsoft Flight Simulator\MISSIONS\ACTIVITIES\SWS-BUSHTRIP-OKAVANGOANIMALSPOTTING_SAVE\SWS-BUSHTRIP-OKAVANGOANIMALSPOTTING_SAVE
And as we are on this. Sometimes the Navlog is missing upon start of a leg, making it virtually useless. In this case you can copy the complete [OriginalFlightPlan] block from the oldest .flt file with the highest numer, e.g. _0002, into the file named above.
Taking again the Okavanga Addon as an example. Copy the complete [OriginalFlightPlan] block from
C:\Users\micha\AppData\Roaming\Microsoft Flight Simulator\MISSIONS\ACTIVITIES\SWS-BUSHTRIP-OKAVANGOANIMALSPOTTING_SAVE\SWS-BUSHTRIP-OKAVANGOANIMALSPOTTING_SAVE_0002\SWS-BUSHTRIP-OKAVANGOANIMALSPOTTING_SAVE_0002.FLT
(or whichever your oldest is), to
C:\Users[MyProfile]\AppData\Roaming\Microsoft Flight Simulator\MISSIONS\ACTIVITIES\SWS-BUSHTRIP-OKAVANGOANIMALSPOTTING_SAVE\SWS-BUSHTRIP-OKAVANGOANIMALSPOTTING_SAVE\SWS-BUSHTRIP-OKAVANGOANIMALSPOTTING_SAVE.FLT
This last finding is not originally from me but I’ve learned it from another contribution here on the form.
If you choose the developer mode to change time (and/or plane), which can be done, there is a chance your completed legs will not be granted.