We have a 18 month old terrier. She is a lovely dog. We feed her twice a day morning and evening and take her out for a walk at 11-12 in the morning and she does her potty after a 10-20 minutes walk. But I am returning back to work in the morning and have to change our walk time to 4-5 pm. But she could not wait till I came back home and went potty in the house. How do I adjust her routine? Please help.