It's worth mentioning that if you have characters on other servers you wouldn't play due to the wrong name/look, you can use the Fantasia from the vet rewards to change their look, and you can use the forced name change if another character with the same name exists in the server you're transferring to to change their name. You can (with a standard sub) make another character in your home world with the same name as the one whose name you want changed. e.g.
I have John Doe on Cactuar. He's a male Hyur. I want a character named Rhee Mahni on Balmung, who will be a female Miqo'te.
I use Fantasia on John Doe to make him a female Miqo'te.
I create a new temporary character on Balmung named John Doe.
I transfer John Doe (now a female Miqo'te) to Balmung. John Doe already exists as a name - I'll be prompted to change the name. I rename the John Doe from Cactuar Rhee Mahni. Ding! I now have a female Miqo'te called Rhee Mahni on Balmung while making use of my old abandoned character from Cactuar, John Doe. I am spared some leveling, and will now party hard.
I have John Doe on Cactuar. He's a male Hyur. I want a character named Rhee Mahni on Balmung, who will be a female Miqo'te.
I use Fantasia on John Doe to make him a female Miqo'te.
I create a new temporary character on Balmung named John Doe.
I transfer John Doe (now a female Miqo'te) to Balmung. John Doe already exists as a name - I'll be prompted to change the name. I rename the John Doe from Cactuar Rhee Mahni. Ding! I now have a female Miqo'te called Rhee Mahni on Balmung while making use of my old abandoned character from Cactuar, John Doe. I am spared some leveling, and will now party hard.