Yes, you can.
If both of your purchased units details (mobile number) is the same registered with the developer, you can switch between unit A and unit B easily. To switch, you may go to the Taman section, click on the taman logo/name. Your other unit number will be shown to select.
If the mobile number is different for both unit, you need to request to the developer team to link the unit from their end to your current ID.