CEDICT
to be just about to (do something); to be on the point of
Wiktionary
即将、刚要做某事。
重編國語辭典
She was about to go out.
She was about to leave.
She was on the point of leaving.
Source: Tatoeba
I was about to change it.
I'm going to check.
She was about to leave the house.
She is just going shopping.