Okay first you need to get the Pirate Costume buff from a wand or from inn...
To change form you just need to relogg .. nice and easy
And the flightpath trick is when you got a pirate form then is possible to use FP with.. If you got goblin and can use it relogg till you get a gnome or undead or something so you can go on flightpath...
Then you take FP to a location (same where) and when you are in air relogg till you get Goblin form.. Voila! you fly slow without and gryphon!