how to change luks password

[Bruno Wolff III]

On Sun, Mar 03, 2013 at 21:54:10 +0100,
   Heinz Diehl <htd at fritha.org> wrote:
>On 03.03.2013, Klearchos-Angelos Gkountras wrote:
>
>> how to change the password for thesse partitions
>
>"cryptsetup luksAddKey" does that.
>
>> or I will do that manually one-by-one ?
>
>Yes.
>
>In fact, you can't change a LUKS password directly. First, you have to
>add the new password, then you can remove the old one. See option
>"luksKillSlot".

Note that those don't change the key used to encrypt the data. They change 
the keys that can be used to decrypt the actual keys. Depending on why 
you want to change the password, changing the key as above might not 
be good enough.