looking for 20 years for this one

I have vague memories of a female singer singing something like
"Hello, Goodbye"
"I know the reason why"

I have trawled the internet, to no satisfaction
the song was definitely written in the 1970s or 1980s and is probably American

It is not The Beatles, Soft Cell or Phil Collins

It has nagged me for years. Any clues?

You said female singer.. but are you thinking of "Hello" by Lionel Richie.

Hello, Is it me you're looking for? I can see it in your eyes, I can see it in your smile... blah some words here.. I love you.

This one's a slow ballad.

No, its not that one, thanks