Check out the FAQ on this: *[What is the etiquette for modifying posts?][1]*

You can also take a look at: *[Should ‘Hi’, ‘thanks’ and taglines and salutations be removed from posts?][2]*

And finally, check out all the questions here [tagged as **editing** or **etiquette**][3]

  [1]: https://meta.stackexchange.com/questions/11474/what-is-the-etiquette-for-modifying-posts
  [2]: https://meta.stackexchange.com/questions/2950/should-hi-thanks-and-taglines-and-salutations-be-removed-from-posts
  [3]: https://meta.stackexchange.com/questions/tagged/'editing'%20or%20'etiquette'