A letter of recommendation can be a powerful tool in advocating for service dog access in areas where it may be challenging or restricted. When a letter of recommendation comes from a healthcare professional, such as a doctor, it can help establish the need for a service dog. The letter explains how the service dog is necessary to mitigate the disability. Meanwhile, a letter from a dog trainer or other expert can describe the service dog's training and behavior, showing that the dog is well-behaved and trained to perform specific tasks. An endorsement can address objections about the service dog's presence in a particular area due to allergies or other concerns. Most importantly, the letter can reference the Americans with Disabilities Act (ADA) and explain that handlers are legally entitled to access public places with their service dog.