Dogs handle name changes very well. It's recommended to give a new name with every change of ownership. Behaviorists often say to give them a positive name which doesn't sound like "no" (or whatever word you use in place of no).
For instance Cujo has the no oh and is negative in sentiment even when joking.
Doesn't she also have other nicknames? Most animals go by a few names. Try one of those instead.
Her pic reminds me of Pebbles. If you really don't want to change, maybe just alter it to Goa or Way-way (Wei Wei).
Edit: You can make a name change immediately. There is no adjustment period in animals. Associate it with a treat and done.