How to stop blocking

How to stop blocking I usually don’t stutter when I’m alone but when I’m talking to someone face to face in real life looking into their eyes, there are words that I will block on. But when I’m alone, I can say those words fine. What can I do to emulate an environment that is similar to this to train my brain and mouth that I can say this and that everything is ok? Is there any way we can mimic an environment where we’re talking to someone? How can I stop blocking?