An approved request for flexible working will usually lead to a permanent change to your employment contract. There will be no automatic right to revert back to your previous working pattern. It is possible occasionally that a manager may be able to agree a fixed-term or open-ended but temporary arrangement with an agreed review period.
Give some thought to the financial implications for your salary, pension, benefits etc. These may be balanced by reduced childcare or travel costs, but it is important that you are well informed about the impact and you should seek advice from relevant people if you are unsure.
If your post is externally funded you may need the permission of the funding body (for example a Research Council) as well as your manager to change your working hours.
Your manager is more likely to be able to respond positively to your request if you have thought through the implications for your colleagues and for the service you provide. If there are disadvantages you should try to consider how they could be overcome, or what benefits might outweigh them.
