Q: As a 15 year old, I went through the OA Ordeal. Now, as an adult, I am a den leader for my son's Cub Scout den. Can I wear the symbol of the OA on my den leader uniform?
A: Once a Scout or Leader goes through his Ordeal, he is a member of the Order of the Arrow for the rest of his life (as long as he is registered with the BSA). As he moves to new councils, he needs to connect with the local OA lodge at each place to continue his active membership. Generally, all you need to do is to pay your dues in your new lodge.
Once you have paid your dues and are an active member again, you can then wear the OA Lodge flap on your uniform. This is true for all adults registered with the BSA, no matter what part of the program (Cub Scouts, Boy Scouts, Venturing) they are currently in.
You should contact your current council's service center. Explain the situation, and they should be able to tell you how to pay your dues and acquire a lodge flap. They can also put you in contact with the local lodge leadership, so you can become an active OA member.