'Can I change the words?'

It’s a bit like how many fairies on a pin head.

Much debated by actors in bars.

There is no one answer to the question, but even if there was - what good would that do you?

Treat each situation as needed and as dictated.

For a typical TV audition where a particular tone is needed, a particular type of role, then focus on that. The words can be secondary. 

If there are medical, military, or legal terms, these must be exact. Part of that reason is to show the producers you can handle that language.

Some projects demand lots of improvisation, and others are letter perfect. You adjust and do your job. As a professional, you fulfil the director’s vision.

As far as casting goes, they don’t check you word for word, but rather want to see if you suit the role, look right and have caught a colour that helps out the episode.

In acting class try working letter perfect for a while. See how that suits you. Then, try only knowing the gist and saying it mostly in your own words. See how that goes.

Don’t get sidetracked by watching interviews with movie stars saying how they improvised every line and then think: ‘Ha, that’s the answer!’

Big movie stars can change the text to suit themselves.

Student films, web series, short films, low budget features are generally all open to changing the lines and, in fact, most often, the director is changing the lines as they shoot.

Focus on playing the situation truthfully and simply as you - they’ll let you know about the dialogue.