usually, a script (patter) is fixed
in most videos / dvds, you see magicians talking about "patter"
"we put the card in the middle of the deck and it always rises to top." etcetcetc
that's not patter. that's describing the effect.
"patter" would be something like...

m: "have you ever owned a dog?"
a: "no"
m: "great! now's your chance. use your imagination! seeing how you were staring at the hot chick who just walked past us, i'm sure you have a great imagination, right?" *pause for laughter*
a: *laughter*
m: "awesome. now imagine you're going to a pet store that has many puppies for you to choose from. *fans cards out* look at them. aren't they cute?"
a: *laughter*
m: "great. now i just need you to pick 1 puppy. yes, in case you haven't realized, just pretend these cards are puppies, alright? use your imagination!"
a: *tries to pick a card*
m: *does the "forcing a card" gag* "sometimes, certain puppies are just attracted to you"

i'm not going to carry on
you get the drift, right?