Table type change. Convert data

What causes this issue?

The table type was changed from POOL/CLUSTER to TRANSP. The table
cannot be activated if it still contains data. Existing data must first
be unloaded. The table can then be activated and the data reloaded.

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

System Response

How to fix this error?

Use the database utility for table conversion (activating the ABAP/4
dictionary table, adjusting the database table and converting data).
You can call the database utility with the corresponding function in
the utilities menu.

Error message extract from SAP system. Copyright SAP SE.