I'd like to ask if there is an ambiguity in the following sentence in terms of the possibility of her late
She said she would be late
In reported speeches we do not change model like would, could, might, yet we use would when we there is uncertainty.
For example :
I will be late, don't wait for me. ( 99 % certainty)
I would be late. ( she could be either late or not)
But in the end we report these different sentences in the same format as
She said she would be late.
Or I can ask what would be natural and explicit conversation in this case so as to avoid misunderstanding, that is
What would she said if she thought she may/might be late.