I am looking for a restaurant in the centre in the cheap price range 
We have 15 restaurants that fit that price range. Is there a specific type of food that you are looking for so I can narrow it down a bit more?
How about an Indian or Thai place?
There are no Thai restaurants. There are three Indian restaurants called Kohinoor, the Gandhi, and mahal of Cambridge. Which one do you prefer?
Are there any spanish food restaurants?
Yes, there is one called La Raza that fits your requests. Would you like me to book a table for you?
Are there any that serve Catalan cuisine specifically?
I'm afraid we don't have any Catalan restaurants. 
Then go ahead and book La Raza for me. We have 4 people at 17:00 on Monday.
That restaurant is not available at that time. Do you want me to try another time?
Can you look for a restaurant in the same area and price range?
I got you booked at the Kohinoor, your reference number is: 7Q9M2VYF. Is there anything else I can do for you?
Okay great! Thank you so much.
Enjoy the rest of your day