That possessive adjective doesn't, but the "long form" ones do. Ex: Nuestro, nuestra, nuestros, nuestras. http://www.spanishdict.com/answers/100031/possessive-adjectives#.VNAPeC5GTuR
Beforehand, you probably mean "its", not "it's".
Strictly speaking, it's correct, as "sus" can mean his (de él), her (de ella), its (de eso), or your (de usted, i.e. formal "you"). However, I can't even think of one real-life scenario for "usted recordó sus llaves" that would mean "you remembered its keys".
When I listened to the computer and typed what I heard, I typed this: usted recordó sus llaves. It said that my recordó was incorrect though. I don't know why because I compared the spellings and nothing seemed wrong. Although, I did press alt + 0243 to get my ó. Would that be the cause of this? I don't know, but could someone please tell me why it wasn't working/I got it wrong?
why is recordo not reflexive? shouldn't we say "se recordo sus llaves"?