I'm not very superstitious, either, but it's a fun thing to do - both the denaming and renaming ceremony. Below is what I've written in the past in another thread, so I just copied and pasted...
I would do the denaming ceremony for both names. Can't go wrong by overdoing it... plus you get to use more of the "spirits"!
I'm not a superstitious guy, but my denaming/naming experience of our Sea Ray has made me think twice......
An interesting thing happened to us when we changed our Sundancer's name. We did the denaming and naming ceremony all in the same day. It was a beautiful, sunny day with light winds and we did it right at the dock, even though the boat would eventually go back out to the mooring. In attendance was my wife, our two kids, my parents and grandmother. The ceremonies, themselves, went off without a hitch as we happily shared the bubbly refreshments with Neptune.
All was well and I motored the boat out to the mooring with the skiff in tow. I tied the newly named Lazy Daze up to the mooring, jumped in the skiff and rowed the 300' back to the dock. I tied the skiff up and started up the ramp to the house when all of a sudden the skies got dark, the wind started howling and what was once a calm, reflective sea turned into a dark mass of mean looking white caps.
At once, I realized that I did the naming ceremony wrong! I did it from the stern when it should of been done from the bow! I wasn't sure what to do as we were out of the bubbly stuff. My only chance was to hope that another form of alcohol would do. I rowed back out, cautiously hopped back on the rocking, and incorrectly named "Lazy Daze" and climbed up to the bow. I braced one leg against each side of the rail at the bow and performed the naming ceremony again.
Hoping I did it correctly, I made my way back into the skiff and back to the dock. As I finished tying the skiff to the dock, I stood up and looked out across the sea to our boat. Within the next 60 seconds the skies lightened, the seas calmed and Lazy Daze sat still and happy... even brightly gleaming as the sun broke through the clouds. Lucky for us, Neptune is a Miller Lite fan.