It doesn't matter whether he does or doesn't: if we refuse to sell him then he stays. The transfer request may remain in place but there's nothing he can do about it as nobody else can sign him until June (or May, or whenever it is the next window opens).
If his Agent told him that he could get him a transfer to another club plus higher wages then the Agent will be out of a job at 23.01 hrs if he's still an Albion player
If I remember rightly, after murray was asked in the summer if he still wanted to leave and his response made it sound as if his previous transfer request expired when the window closed. I can't remember the exact way he said it, but it was something along the lines of "I put one [transfer request] in during the last window, and haven't put a new one in this time, I think the last one ran out" If I wasn't so tired I'd look for the quote in the argus, but it definitely left me the impression that the request expires when the window closes.