Most employers have now abolished a set retirement age, but your pension scheme will still have a 'normal retirement age' while the auto-enrolment rules take age into account (you will not be auto-enrolled beyond state pension age, but could still apply to join your employer’s workplace pension). If you are in a 'money purchase' (DC) scheme, you will probably be able to go on paying into the scheme, but you should check if your employer will still contribute.
You should also be aware that, although you will probably be able to buy a bigger annuity if you leave it later, the extra income may not make up for not getting it earlier. You should also remember that if you have chosen a 'lifestyle' investment arrangement (i.e. one that switches your fund into less risky investments automatically over a period leading up to your normal retirement age), you should tell your pension provider if you have decided to take your pension at a different age.
If you are in a salary-related scheme, you will need to ask what options are available to you. You may be able to go on contributing, or your accrual may stop. Your pension may be 'actuarially enhanced' if you don’t draw it until later, but not all schemes do this. If you are cutting your hours, you should find out how the scheme calculates pensions for part-time workers.
If your salary is going to reduce for any other reason, you should ask how this will affect how your pension is worked out. It may transpire that it is not a good idea to stay in the scheme.
You can now also claim your pension and continue to work for your employer if the scheme rules (and the employer) allow this. This will make it easier for people to retire in a flexible way by letting people take some pension while still working part-time for their employer. You will need to look at your options closely and ask your employer or the scheme administrator for more information.