I'm reading a book where the author used to stutter during his youth, and he started using something called speech 'crutches' to get through some of these conversations. He mentioned 8-9 crutches that helped him. One of those crutches has helped me manage my speech during these quick interactions. Here it how it works: Lets say you feel you're gonna block on a word. Try to drop the first word/syllable. 99% of times other people can understand what you're trying to say. For example, if I feel I'm gonna block on the word 'renovating', I drop the 'r' sound, and just say '..enovating'. As in "I'm ..enovating my ..itchen this summer". It might make you sound like you've a lisp, but that's better than not being able to communicate. Similary, if I cannot say the word 'decline', I drop the 'd' sound, and just say '..ecline'. "Hello, my transaction got ..eclined. Can you please check?" I've gotten through many conversations using this crutch, and being able to bypass my blocks has made me more confident in those situations. It takes getting used to, so I recommend practicing this a lot in front of mirror. I'll give the name of the book and the author if you like...