A new baby to love , and rename

My cousin is stationed in San Antonio right now, but has to quickly go to California.
He has ......... well...........HAD ....... an akc registered Golden Retriever named buttercup.

I absolutely love his dog.
She is sooo sweet, laid back, kiddo friendly, well trained.. just an all around happy content lap kinda dog.

Well, I got a message friday that they had to leave her with someone else because where they are moving, doesn't welcome dogs with out a big deposit.
Also, after a year and a half of horrible allergies, they take their son in to have an allergen test, and wouldn't you know... hes allergic to dogs.
Pretty bad from what I understand.

She is so pretty.






So sweet




And has a horrible name - Buttercup-




Now I have 3 'babies'

Jillian, kitten and... the nameless wonder. ?

I still use buttercup, but I want to change it.
Is it easy to change a dogs name?
Will changing her name effect her training?

She is trained in almost everything.
Leash, house trained, basic commands, tricks, doesn't run out the door just because it is open, knows how to stay.. etc..

And they all rely on getting her attention first .
Example
- Buttercup, stay-

So, Im kind of at a loss.

Ian says name her deogie.
Pronounced - Dee-o-gee
Meaning - d-o-g

HATE IT..

Any ideas?