At the age of 54, when most people would be looking ahead to retirement, banker Johnny Tan - now 67 - was asked to take on an entirely new role.

By that stage, he had worked with Standard Chartered Bank Singapore for close to 40 years, progressing from a clerical role to managing branches.

But after all those years on the retail side, he was given the task of heading operations for the bank's unit for small and medium-sized enterprises (SMEs).

It was not an easy transition.

"By the second or third day, I thought of giving up. It was a totally new place with different functions," says Mr Tan.

The products and clients changed, as well as the staff and processes he had to manage.

But he persevered and continues to head the unit today, 13 years later.

He declares: "Our mindset must be to learn and be prepared to accept changes all the time. If something is given to you, just do it."

Indeed, StanChart says he has held 11 jobs with the bank over the course of his career.

His first job was as a clerk helping with cheque deposits in StanChart's Battery Road branch.

Then, to get up to speed with the latest in the banking industry, he went for a diploma course during his first few years of work, to learn about topics such as banking law, accounting and the finance of international trade.

He also attended courses at the bank's offices in Kuala Lumpur and London early on in his career, meeting colleagues from around the world and picking up public speaking skills.

In 1975, he was promoted to branch manager, running a small branch in Changi which served mainly pilot trainees and trainers as well as residents from Pulau Ubin, Pulau Tekong and Changi Village.

Although he did not have a formal training and progression framework to follow, Mr Tan accumulated a wealth of experience as he oversaw different bank functions in branches such as Jurong, Selegie and Battery Road.

"Every place I worked, the knowledge and experience stayed with me," he says.

For example, learning how to manage staff in his branches and troubleshoot customer complaints later served him well as he implemented new procedures in the SME banking unit.

Noticing that his staff had a culture of staying late at work, he introduced a cut-off time for the bank's relationship managers to pass cases to his team each day.

He also has to resolve relationship managers' issues as quickly as possible, so that they can help clients.

When the bank introduced a new sales verification process to allocate commissions for staff, he worked out details such as what documents were needed from relationship managers and how to get staff to input details into spreadsheets.

StanChart Singapore chief executive officer Judy Hsu says that Mr Tan "always keeps an open mind, takes initiative to add value and always has the customer at the centre of what he does".

She adds: "Most importantly, he makes an effort to learn new skills and is always willing to take on new challenges."

Mr Tan has been on re-employment contracts since he turned 62, with his current contract lasting until next year.

Even now, after 50 years with the company - making him the longest-serving employee across the bank's worldwide network - he feels he still has much to contribute, such as through developing younger colleagues and helping them use their strengths to their advantage.

"You must be willing to share knowledge with younger colleagues, and make sure they can learn from you," he says..