When you work part-time, or when your contract is changed to part-time during your PhD, law requires that the employment contract should be extended proportionally.
A request to work part-time can only be refused if it has serious harmful consequences for your employer, for example if your project is externally funded and the funding has to be paid back if the project is not finished timely. However, some external funders (e.g. some NWO-funds) have options for freezing the fund in the case of parental leave.
Unless ‘business interests’ do not allow for it, you are entitled to a so-called ‘flexible working hours’ arrangement. This means that you can come to an arrangement with your manager about weekly working hours that deviate from the customary 38 hours per week. You may work two hours extra or less each week. With this, you either relinquish 96 holiday hours on an annual basis if you work less, or you receive extra holiday hours if you work more.
The arrangement about how to apply the flexible working hours scheme has a duration of one year. If unforeseen circumstances make it imperative to change the arrangement, you should discuss this with your employer.
