you cant convince some one to put you in gryffindor. you have to be picked when you are sorted when you first enter Hogwarts based on your attributes
Probably Gryffindor , because Harry and Ginny both go to Gryffindor.
Severus Snape put it there at the request of Dumbledore.
Severus Snape but it was a pond not a river.
You can convince someone that karaoke is good by constant exposure and lots of practice.
To convince someone you must sway them.
The Sorting Hat initially wanted to put Harry in Slytherin; but seeing as Harry already had a bad impression of Slytherin he asked not to be put there, and the Sorting Hat put him in Gryffindor, if Harry hadn't said, "Not Slytherin, not Slytherin" than he most likely would have been in Slytherin. but he was placed in Gryffindor.
Godric Gryffindor
Come on to them.
Go go gryffindor! Go go gryffindor! Go go gryffindor! Go go gryffindor! Etc :D
Godric Gryffindor.
It may not be a "reason" to you, but I'm sure your parent has one, and if they can convince a judge that they have a valid one, he will issue it.
If you expalin what an "AIM" is, perhaps someone can help.