When you adopt an older dog, you often don't know his history. This might include not knowing his name. Unfortunately for many older dogs, they come with a past they can't share with us. Some of these dogs haaave a past of abuse and a really difficult life. Some came from loving owners who decided they couldn't care for their dog anymore and left without sharing his story.
If this is the case with your older dog, you may need to rename him and train him to recognize a new name. Training your dog to learn a new name won't be terribly difficult because it will be more a matter of repetition than anything. However, your dog may become frustrated because he came to you with an identity you know nothing about.
When training your older dog to learn a new name, you're going to have to repeat it quite often. Not only in general conversation or in getting your dog's attention to go outside, but every time you talk to him, you may have to say his name several times. This will take some time, and both of you may become frustrated. Just remember youR older dog can’t communicate his frustration with you, so try to be patient with him as he gets to know not only his new name but also as he adapts to a big change in his life. There might be times when you speak to your dog and he looks past you or doesn't respond because he might be used to hearing a different greeting. If your older dog has been abandoned or rescued, he may be a little nervous and apprehensive about a lot of things. Patience and repetition will be key.
Make sure you are patient with your older dog as he learns his new identity. Show him lots of love and attention and provide him with lots of treats see. Each time you offer him a treat say his new name so he associates the reward of food with hearing that name. You don't have to schedule sessions to teach your dog in your name, however, take some time to spend with him one-on-one without distractions teaching him the new name you've chosen for him.