Which statement can be used to change the contents of a row of data in an internal table?

The statement that can be used to change the contents of a specific row in an internal table is the 'Modify table' statement. This command allows you to update existing entries or change individual fields of a row in an internal table. It requires you to specify which row you want to modify, and it can also specify the new values for one or more fields of that row.

For example, when using the 'Modify' statement, you typically will provide the index or a key for the row and the new data you wish to set. This is essential for scenarios where you need to update records based on some condition while preserving the structure and order of the internal table.

The other statements have different purposes focusing on populating the internal table rather than altering existing rows. 'Append table' is used to add new rows at the end, 'Insert table' allows you to add new entries at specified positions, and 'Update table' is generally not recognized as a proper syntax in ABAP for modifying internal tables. Thus, 'Modify table' is the appropriate choice for updating the contents of an existing row in an internal table.