Transfer of articleship in 2nd year

A CA having 10 articles registered under him. Out of which 1 article has completed his articleship of 3 years but documentation of completion /termination is pending and vacancy is available against that student in ICAI's members card. So should I get transfer/registered as a article under him before previous student's completion or his documentation of completion is compulsory for my transfer/registration as article. Plz advice me.