It is possible to delay a period for an event, holiday, or exam. For people not on hormonal contraception, a doctor may prescribe a short course of a progestogen tablet to take before the period is due. For people already on certain hormonal methods, such as the combined pill, the timing of the pill-free break can sometimes be adjusted to skip a bleed.
This is generally safe for occasional use in suitable people, but it is not right for everyone, and the correct medicine, dose, and timing depend on your situation. That is why it should be set up through a clinician or appropriate pharmacy service rather than improvised.
Plan ahead, as the medicine usually needs to be started before your period is due. Mention any health conditions, current medicines, and your contraception so the clinician can advise on the safest approach for you.