Change in BEGIN_DEPR_DT

I have assets start in Project Costing and once a threshold is met, they are created via Express Asset Capitalization. As they are still WIP, they are initially given an In-Service date of the expected start. They are created as non-depreciating assets. Once the project has reached the point where we know the occupancy date, they are then switched from WIP to a depreciating Profile/Category. However there seems no way to enter a BEGIN_DEPR_DT on the Define Tax/Depr Criteria page as that field is read-only and the record shows it as such.

How can I add a Begin Depreciation date?