Change TextFormat

1

Hai all…

I have specified a text format to a particular text field.
and after some time i need to change the same text into another format…

is there any way to do???
i diid in the normal way…but was not working.
the code is like…


 
myDefaultHDecor = new TextFormat();
      myDefaultHDecor.underline = true;
      myDefaultHDecor.bold = true;
      myDefaultHDecor.color = "0x000000";
      myDefaultHDecor.font = "arial";
      myDefaultHDecor.size = 15;
txtBulletin.setNewTextFormat(myDefaultHDecor);