No, as the address of the property has to be identified in the Power of Attorney. You can however, sign a letter of authorisation to allow someone else to represent you for the selection of flats. The form of the letter can be found here: https://www20.hdb.gov.sg/bp13/bp13005p.nsf/8fa3e67377da0a35482586a1001e18e1/$FILE/Authorisation%20To%20Select%20a%20Flat.pdf