A phrase which is employed as an attempt or means of remaining on good terms with a person who one does not particularly like or with whom one does not truly wish to associate.
"Oh...hey. Um, yeah, I'm well. You? That's, uh, good. Yeah, we, uh -- yeah, we should do something sometime. Totally."
A polite way of saying "I know you, but I don't like you well enough to make definite plans, so I'll leave you thinking that I at least considered having a night-out with you."
Oh my God..Sarah?? Wow, long time no see! Hey, I can't stay to chat, but we should definitely do something sometime!