What is the suggested attire for a retired servicemember attending an Army ball?

I have an upcoming Army ball in a few weeks. I have attended many throughout my career, but this is my first as a retiree. Normally it is my dress uniform (as identified in invitation) and a clean shaven face. Now that I am retired I am bearded up and not looking to shave or put my dress blues back on. What is an appropriate attire for a retiree (invitation said semi-formal)? I am looking for a few different suit types (suits are new to me). Also, is there a recommended lapel or something that one should wear or is suit and tie enough?