Hi mate and welcome,
I purchased my 563 a few months ago and want to change her name from "Bultaco" to "Storm Trooper" but I'm a very superstitious bloke and renaming a boat is fraught with superstition. I recently came across a fantastic "Ode to Neptune" to de-name and rename a boat.
I'm yet to do this (feel a little silly reciting this at the launching ramp or with boat in the backyard

so I'm going to de-name my boat when she is actually on the water (which makes more sense to me as well).... then the next time she is ready to relaunch I'll christen her with a small bottle of bubbly with her new name.
I reckon the 'ode' will well and truly solve any superstitions I have
Here it is:
Yacht de-naming ceremony
Here’s the actual ceremonial recitation:
“In the name of all who have sailed aboard this ship in the past, and in the name of all who may sail aboard her in the future, we invoke the ancient gods of the wind and the sea to favor us with their blessing today.
“Mighty Neptune, king of all that moves in or on the waves;
“And mighty Aeolus*, guardian of the winds and all that blows before them:
“We offer you our thanks for the protection you have afforded this vessel in the past. We voice our gratitude that she has always found shelter from tempest and storm and enjoyed safe passage to port.
“Now, wherefore, we submit this supplication, that the name whereby this vessel has hitherto been known, ( ), be struck and removed from your records.
“Further, we ask that when this vessel is again presented for blessing with another name, she shall be recognized and shall be accorded once again the selfsame privileges she previously enjoyed.
“In return for which, we rededicate this vessel to thy domain in full knowledge that she shall be subject to the immutable laws of the gods of the wind and the sea.
“In consequence whereof, and in good faith, we seal this pact with a libation offered according to the hallowed ritual of the sea.”
Now you can pop the cork, shake the bottle and spray the whole of the contents on the bow. When that’s done, you can open another bottle for yourself.
How long should you wait before the new naming ceremony? There's no fixed time. You can do the renaming right after the denaming, if you want. But most of us would prefer to wait at least 24 hours to give those sneaky sea demons time to clear out.
(* Aeolus, as I'm sure you know, is pronounced EE-oh-lus, with the accent on the first syllable.)
New Christening Ceremony
The traditional ceremony calls for a bottle of champagne to be broken across the vessel’s bow. On small boats, the bottle is usually enclosed in a fine-mesh net so that dangerous splinters of glass do not escape. Alternatively, you may open the bottle and spray the contents on the bow and forward topsides.
If you have serious objections to the use of alcohol, use any sparkling non-alcoholic drink instead. The gods will not despise you nor punish you in any way for acting according to your true conscience.
The christening is very short and simple. The essential parts are the new name, and wishes for fair winds, safe passages, and good fortune. You can make up your own ceremony if you like, but here is one example. It is to be spoken immediately before the breaking of the bottle or the spraying of its contents:
“I name this ship (________). May she bring fair winds, safe passages, and good fortune to all who sail on her.”
(From How to Rename your Boat and 19 Other Useful Ceremonies, Superstitions, Prayers, Rituals, and Curses,published by Paradise Cay Publications.)