Blair Brown called for a line when she was in the New York run of Humble Boy when it was in previews. There are numerous instances when an actor is replaced very late in rehearsal or in previews and they have to go on with a script in their hand for the WHOLE performance. Everyone cuts them some slack.
In almost 300 performances, Cherry has flubbed twice. Both times she was under the weather. I saw her on the Thursday night last week and she said she was feeling weary and when I commented that she had a 9 show week to get through, she was like "Lord, I know." I'm sure other actors who never miss (Chita, Harvey, etc) have gone on when they haven't been feeling great and have had a screwy performance or two in their time. Quite as to why this has to be such a big deal is beyond me.
Nothing precious, plain to see, don't make a fuss over me. Not loud, not soft, but somewhere inbetween. Say sorry, just let it be the word you mean.