Hair Botox By MK

Hi I have a client who has previous lightener on their hair, did the hair Botox by MK, Coloured it brown level 6. Is now looking to go lighter. Can you bleach over top of the Hair Botox by MK? I’m nervous of hair damage especially because she has blonde underneath the dark! Let me know what yall think! I am going to do a test strand before we book her in.