Blocking of user threads

Hello, We are using Informix Online 7.13. The problem is that usually the user threads get blocked and if the applications which was accessing the thread exit the database which that thread was accessing gets blocked. Hence to access that particular database once again we need to bring the Informix to offline mode once again and in that process destroying other databases also. Is there a way in which to kill that particular user thread which has blocked. Or to remove the lock from the database. I have been unable to remove the lock from the Informix administrators mode. Deepak