how one user can change other user objects- urgent

My user id is changed from userxx to useryy,

I have some objects which userxx developed and activated, so now I want to work/access the objects logging with useryy.

I get the message saying userxx has the object locked, you can trafnsfer objects to ur change list but,

when I ma trying I see the transfer option on those change list is disabled.

ples reply

thanks

KK