Yes you can change anytime.. Buy wait till get MIB..And for swift code. The best one you can find on sbi website... SBININBBFXD which you can find here. https://www.onlinesbi.com/nri/remittances/sbinri_rem.html. Previously I used the swift code which bank provided me.. But they charged me a lot. Then talk over phone with sbi customer care they provided me this central swift code which is faster and charges less fee..