Amint, the process will be faster and hassle free if you were to sell directly to bumi, however if u want to sell to non bumi u must ensure and prove that you've advertised and tried selling to bumi but no bumi takers interested in your unit after a period of time.

An officer from state department once explained to me that you also must have valid reasons to dispose your property to non-bumi i.e
1. To cover heavy medical expenses (operation, chemo, transplant, etc)
2. Facing near bankruptcy
3. Owe money to many alongs

She mentioned that the usual reasons of upgrading house, transfer to another state, etc are not strong enough for bumi to non bumi conversion.

Hope this helps. Cheers!