Can i still use the single journey left from my 330HKD airport express travel pass after 3 wks ?

If my stay is finished in Hk after 3 days and use only one journey from my airport travel pass, can i use it again when i visit HK in 3 wks and still allowed 3 day MTR pass? rhank u so much..and may i pls know what shuttle bus to use going to HK island?