Look for the underlying cause
Sudden changes in behavior can have medical causes. Begin with a veterinary examination, especially when the problem involves pain, house-soiling, anxiety, aggression, or a significant personality change.
Get qualified help
A veterinarian or credentialed behavior professional can help distinguish training issues from fear, anxiety, pain, or other medical concerns. Many common problems improve with a consistent plan, appropriate exercise, management, and realistic expectations.
If rehoming is necessary
Be completely honest about the dog’s medical history, temperament, training, bite history, and behavior around children and other animals. Screen potential homes carefully, use a written transfer agreement, provide veterinary records, and never advertise the dog as “free to a good home.”
Contact an experienced rescue
A breed rescue can explain available options and its intake process. Capacity varies, so contact the organization as early as possible and be prepared to help with records, transportation, or temporary care.