Auto text reply while on the phone

I know I know this,but can't remember how.......

If I am talking on the phone and a call comes thru,I hit the text symbol and choose one of the messages.......

Now,here's the part I forget..........how do I change those messages?? I'm sure it's one of DUH moments.......

Thanks for your help..I have tried googling the answer without any luck at all.

Accepted answers

Phone app > Menu > Settings > Quick responses

Phone app > Menu > Settings > Quick responses

Thanks............Have no idea why I keep forgetting this.!

It's easy to forget if you don't use it often.

Like the French lessons I took in school!