might need some help here

hello this is the first time posting on this page and well i need some help figuring out what to do because i might need to take three days off from work I’ve been working for target for around 3 years now in many different positions and have trained other employee’s. recently i got notified my grandmother has been hospitalized in a different state where she lives and my mother wants me and her to go see my grandmother as shes in critical state and has been there for around 2-3 days by now. my big issue is that i don’t know when we are leaving on a flight the flight there takes a few hours same back but we would be there the entire three days so i don’t know what to do i don’t wanna call off two days and lose money one option I’ve been thinking is moving around my days off by asking my HR lady to do that for me and then call in one day but work at-least enough to sustain myself pay wise any advise?