How do you stop doing missions in gta v?

you should have gta 4 , lost and damned or Ballad of tony and have internet connected on your ps3 or your computer (the ways necessary for quiting a mission on any of these 3 games of gta, by the way only on these 3 games of gta have a quiting trick but you should have internet connected and its also necessary). so the way starts like this

1. you go to do a mission then afterwards you think that you dont want to do that mission.

2. if you have a partner in that mission, kill him to fail the mission and get out of that mission and in this no internet connection needed.

3. but if dont have a partner then just take your mobile phone (in the game) then select multiplayer then quick game then just any of those games , then when you are inside the multiplayer game quit the game and you can quit the missions on Grand Theft Auto 4,lost and damned and ballad of gay tony.