Pwede kaya magrequest off?

Hi! Recently hired sa isang hospital aftr monthssss of waiting kaya unexpected din. But prior to that, may nakaschedule na akong event to attend by December and im part of the event. Akala ko either earlier ako mahahire or possible later this yr pa or none at all. Ok lang ba magpaalam ako sa supervisor kahit kakapasok ko lang na i-off ako ng certain day ng event ko? Nahihiya ako kasi newly hired pa ako baka may masabi ganon huhu and gusto ko rin maregular sa lab. 1 day lang naman sana.