Vampires and alternate forms?

[Ogrork the Mighty]

Can a vampire change into a bat, then into a wolf, then back into a bat? The SRD indicates that a vampire can maintain its form until it assumes another or until the next sunrise (IIRC). But it isn't clear if it can assume a single form multiple times.

 

[Patryn of Elvenshae]

He can change as often as he wants, into whatever forms he wants.

SRD

A vampire can assume the shape of a bat, dire bat, wolf, or dire wolf as a standard action.

...

It can remain in that form until it assumes another or until the next sunrise.