changing a cached domain windows logon password on a laptop with a command/regedit

hi all

when logging onto windows xp on a laptop and the laptop is on a domain, i seem to have a problem occasionally with the cached domain password... i have to change my password every month... sometimes this is done from a desktop pc in an office, then... when i get home and use my laptop i have to logon with the cached password (old password) and then use my new password for vpn... it takes 10 to 15 mins before im prompted to lock my laptop (screensaver lock) and unlock with domain password so windows has the current credentials...

is there a command i can use to forcibly change the cached password so as to speed up this process of waiting to lock my laptop so as the cached password is changed to the current one?? obviously the laptop isnt directly connected to the domain until i use vpn so i always have to use a cached password... im sure theres a simple command i can use to forcibly change the cached password or even a registry edit... can anyone help me out? :)

thanks