Backstage.com has a wonderful interview with Phyllis Smith:
In 2004 the company was testing the series regulars for The Office when Smith heard Kwapis say he wanted her to read one of the characters. “I didn’t really think anything about it; I just thought I was being a reader,” she recalls. “I was just hoping I did a good job for the actors.” Over the next few days, Smith heard from other actors in the running that Kwapis wanted her in the show.
“Then when we took people to network, we were walking down the stairs at NBC, and Ken turned to [current NBC co-chairman, then head of production company Reveille] Ben Silverman and said, ‘I want Phyllis in the show. I have a whole backstory for her,’ ” she recalls. “But I’ve been in this business long enough to know that until it’s in writing, I shouldn’t get my hopes up.”
Link: ‘Office’ Space (you’ll need to scroll down the page a bit)