Provide the theme summaries for the following conversation: 

#Person1#: Hi, Kate.
#Person2#: Hi, Don. What a surprise!
#Person1#: Yeah, I saw someone walking like you, but I wasn't sure. We haven't seen each other for how long? Almost three months? But you look quite different now.
#Person2#: Have you noticed what has changed?
#Person1#: Oh, you look quite slender and more vivacious. What have you been taking? Are you on a diet?
#Person2#: Yes. I'm on a diet, but I'Ve not taken anything. I just eat less and exercise more. And it really worked in the past three months. I'Ve lost twelve pounds.
#Person1#: Wow! That's great. I sincerely want to achieve my weight loss goals, but it's difficult for me to keep up the exercise. Also you know, old habits are hard to break.
#Person2#: What kind of exercise do you think I do? I just go to dance everyday after work. I'm taking an amateur dance class. I dance two hours everyday.
#Person1#: Dance? You only go dancing? That's not hard. I can do that.
#Person2#: Sure. Join my class next week.

Summary: 
Kate becomes slender and more vivacious and she tells Don that she eats less and takes dancing classes. Don will join Kate's dance class next week.