It's important to know that when you enter into a Salary Exchange agreement there is a change in your contract, to give up part of your salary for a non-cash benefit, such as a pension contribution.

As such there a couple of scenarios you should be aware of:

Once your contract is set up to accept salary exchange, it is very easy to make exchanges for additional non-cash benefits (like increases in pension contributions).

Each time you take on or amend a benefit, your 'Reference pay' will remain the same but 'Gross Pay' will be reduced and the money exchanged into the benefit.

When using salary sacrifice as a pension deduction, you are permitted to opt in and out of the scheme. However, your employer may restrict the amount of times you can do this in a 12 month period due to higher levels of administration.

You may reduce your pension contribution but only in certain circumstances. HMRC accepts that certain ‘lifestyle changes’ may justify changing a salary exchange arrangement before the intended duration has elapsed.

There are no legal definitions of what a lifestyle change is, but it is generally intended to refer to unforeseen life events that will materially alter your financial position. At this time your your employer might agree with you to revisit the salary exchange arrangement to take account of the change in circumstances.

This may happen if the employee has a salary sacrifice arrangement for a set period and within that period an event happens that means the arrangement is no longer suitable.

A full list of acceptable lifestyle changes is given below, but if you suffer consequences of an event not listed you may still be able to make a change if your employer agrees:

Also when you receive a promotion or demotion your contract naturally changes so will be able to alter at these points.