If i change the name to whom have secured all my chests, i can release all if i change the name?
If you change a character's name, it will still have all of the permissions/authority it had with the old name.
The character I changed the name on was co-owner to another house and she could still do everything in that house that her character could do before the name change. Her new name did not affect her ability to be able to secure or release containers or change permissions on containers that she had placed using her old name.
Everything works the same for the character under the new and old names, when it comes to housing.
Akd another thing. I have a little house in atlantic. I've cancelled the char who had bought but in the sign there is yet her name

But it ìs a different case. I've cancelled the char and not changed her name.
When saying
"cancelled" I am assuming you mean you
deleted the character, is that right?
If the character whose name is on the house sign is deleted, that character's name will remain on the house sign. I don't know how you could change the house sign in that situation. I never tried. I just left the name as it was.
You might try accessing the sign with the new character you made to replace the deleted one. I don't think that would work, but you could try. Perhaps you could contact a GM about it.
BlissMarie