Good afternoon, do you need a power of attorney for the child if he/she leaves...

No, a power of attorney is not required. The child can be accompanied by one of the parents, grandmother, grandfather, adult brother, sister, stepmother, stepfather or other person authorized by one of the parents; in order to leave accompanied by one of the parents, grandmother, grandfather, adult brother, sister, stepmother, stepfather, there must be documents confirming the family ties of the accompanying person with the child (birth certificate, marriage certificate, etc.); the notarized consent of one of the parents for the child's departure abroad is required in the case of the child's departure accompanied by a person who is not one of his parents, grandmother, grandfather, brother, sister, stepmother or stepfather. You can verify the certificate in the guardianship and guardianship bodies of local self-government bodies.