Changes are not reflected after Editing

There's one that FM scout have released, which I believe is free.

http://www.fmscout.com/a-fm-editor-live-2014.html

Yeah the editor that comes with the game only amends the data used to set-up a new game. If you want to edit a save you will have to pay for the In-game editor via the FM store or FMRTE.

Thx for advice! I made it now!!
But those players in non-officials leagues (e.g. Japan J-league) can not be found in Data Editor...
Is there a way to edit those players??

If you've downloaded an editor data file which adds these players to your game, then just edit the entries within this file using the editor...

You mention the J League players. To get them, you must have downloaded an editor data file which adds them, since they are not in the game.

Load the editor, then load the editor data file, find the respective players you wish to edit and do so accordingly.

There's a lot of help on Google and even within this site - you should really try and search online first for answers to relatively straight-forward queries such as this as you'd find a solution more quicker that way