Reader: In the past, Koby's goal was to become a commissioned officer of the Marines (Volume 1, Chapter 7) but now he wants to be Admiral! (Volume 45, Chapter 453) Would his rank still rise even if he's now a SWORD member whose resignation documents are already formally submitted?
Oda: Yes. Was the explanation about SWORD a bit complicated? In Chapter 1080, Aokiji said "formal submission of documents" "they can be disavowed any time". This means, they entrusted their resignation but they are not fired (cut loose, disavowed) yet. In the case of a Marine soldier getting caught and becoming a hostage, the Marines will acknowledge their resignation there and there and say "that guy is not a Marine soldier!" and forsake them. The ones who are fine with this so they can fight as they please are the Marine soldiers called "SWORD".
Note: This implies that if you are a member of SWORD, your rank can still rise as long as Marine HQ doesn't acknowledge your resignation papers yet. In the case of Koby, he is a member of SWORD and he indeed became a hostage in exchange for the hundreds of Marines that Blackbeard was about to take from Amazon Lily. We just don't know yet if the Marines have already disavowed him at that time. We also don't know if you have been disavowed and then rescued, will you be accepted as a Marine again and then your rank can rise again.