Yes, baselines can always be delivered or accepted. Think of a baseline more of a 'tag' or point in history (so really they are not 'empty' as they contain an ordered list of change sets pointing from the most recent change set in the stream/workspace at the time the baseline was created, right back to the 1st one in the component history). You can create a baseline at any time, and then deliver it, and then create another baseline (ideally with a different name if you really need to make 2) and then deliver that one as well. Those 2 baselines, relative to each other, would be considered 'empty' when comparing both of them.