A 32-year-old multigravida (G3P2) at 40 weeks gestation is admitted to the labour ward in active labour. After 8 hours of labour, her cervical dilation is plotted on the partograph and crosses the action line. She has had 3–4 contractions per 10 minutes, each lasting 40 seconds. Vital signs are stable, and the fetus is in cephalic presentation at −2 station. What is the most appropriate next step in management?