I am considering opening a Joint Account at Bangkok Bank in my name and that of my Thai wife. My query is what happens should one of us die ? Can the surviving partner continue to fully use the Account or would it be closed ?

We have asked that question at Bkk Bk and they said it can be changed to a name only account if and whenever anything happens. 

I asked the same at Kasikorn, Khon Kaen,  and was told the name of the account would immediately be changed to that of the survivor on production of the other person's death certificate.