Dear Raj,
You can add new fields with the help of remodeling.
Steps..
1. Tack a backup of cube where u wants to add a new field.
2. Stop the process Chains Which will feeding the data for cube.
3. Without deleted any data in cube add new field in cube.
4. Create a DSO with same Key Fields and as a Cube with new field which u want to add in cube and get the full load.
please see the attached update.
regards,
Satendra
8099805591