How do you get past the guard in route 8

Go to the house to the right of the guard house and go in. When you come out you will be in a different city then, the city behind the guard house, but to get there you have to go inside the celadon mansion. Once you are inside, go to the room on the right, talk to the old lady and she will give you tea. Once you have the tea, go to the guard and talk the him and he will take the tea and let you continue on you journey.