Westpac Institutional Bank chief executive Lyn Cobley has warned that the looming "transitioning economy" will be characterised by ever shorter cycles of change. "As a bank, we need to think completely differently," she said.Cobley said the average lifespan of a company in the S&P 500 has declined from 61 years in 1958 to 18 years today (although Westpac in its various forms has survived for 200 years, as of this weekend).One manifestation of the rapid change, dating back to about the start of this century is the degree of digitisation by businesses, which banks are recognising, as Cobley noted, pointed out that lending decisions - even those to smaller businesses - can be based on cash flows rather than tangible assets or the family home.While Cobley's fellow execs have been trotting out the line that Westpac is 'a 200 year old start-up', in an attempt to highlight the reshaping going on at Australia's second largest bank (by market capitalisation), the impetus comes from genuine start-ups. While the adjustment to business transformation can be made relatively simply, a workforce in transformation is another matter.Cobley said Westpac was in the middle of a "workforce revolution", with performance reviews run according to very recent business outcomes.