You mean unlock it so that it can be used on any network including 48? You'll need to contact the network to which it is currently locked and ask them about this. Or get it unlocked unofficially in a reliable/trustworthy phone shop or by buying an unlock code online from a reliable/trustworthy unlock code provider.
Hope this helps.
I am not a 48 employee so if you need to contact 48 support then use option 3 or the chat facility here.