So how do I get back to the Command Center if the option to beam down to the CC is gone? Oh yeah, I have to beam down to New Romulus and walk in the front door - after the New Romulus rep intro. So yeah, you are forced, since the promotion mission takes place in the CC, and you can't get back into the CC without beaming down to New Romulus and going through the rep intro.
You watch the intro 1x its unskippable since it is the same intro for every faction.
once you have watched the intro you can immediately beam up and the beam to new Romulus command should be there, as I have done than on all my romulan/remen characters.