Yes you can!
1. Defrost frozen milk (still in milk bag)
2. Pour out what is needed for 1 feed and leave the remaining in the milk bag (remember to put it back in the chiller!)
3. Pour out the remaining BM for the next feed
As long as the milk is used up within 24 hours from the start of thawing, it's fine.
Always remember to practise good hygiene when handling milk.
Wash hand with soap and wipe dry with clean towel.