The edit which corrects the punctuation in the quotation is the following one:
Place a comma between here and the quotation mark:
“I didn’t know you were in here," she said, “otherwise I would have knocked.”
A comma must be used whenever a pause is needed. It also works as a way to separate different ideas and make a sentence more organized and clear, thus making it easier to be read and understood.
The meaning of a sentence can sometimes be changed depending on the position of the comma, as well as whether the person writing chooses to use it or not.
Eg:
"Let's eat, Grandma!" (a comma between "eat" and "Grandma": Grandma is being invited to eat)
"Let's eat Grandma!" (no comma whatsoever: Grandma will be eaten)
