Steven Dietz’s “Becky’s New Car” begins as an occasionally hilarious screwball comedy and gives way to a disarmingly thoughtful drama about the nature of love, fidelity and second chances. Based on the play’s first act, which is snappy and broad and breathlessly paced, you wouldn’t imagine that it could transition so seamlessly into its touching closing scenes. It’s a tricky balancing act, but “Becky’s New Car,” crisply directed by Christopher Wooley, pulls it off. The show, which premiered this weekend at Spokane’s Civic Theatre, stars Kathie Doyle-Lipe as Becky Foster, who has been married to her loving husband, a roofer named Joe (Steven Blount), for nearly 30 years. At home she’s always picking up after her philosophizing grown son Chris (Michael Barfield) and waiting on delivery pizzas. At work she’s perpetually in over her head: As the office manager at a car dealership, she does a little bit of everything, juggling paperwork and angry customer phone calls and staying long past when the doors have been locked.