Yeah with the debug menu/tool, ALT+F12.
https://www.reddit.com/r/KerbalSpaceProgram/comments/2ln35p/any_way_to_cheat_contracts_through_something_like/
And here it explain roughly how to edit the save regarding to contracts change.
https://gaming.stackexchange.com/questions/232034/how-to-bring-back-mysteriously-missing-contract-in-kerbal
Sorry i'm not elaborate more, i'm on my phone atm