>>GETNEXTMODIFIED(0 [, cTableAlias | nWorkArea] [, lNoFire]) returns the first modified, zero if none
>
>Since it can tell if something changed, is there a way to know what changed without looping through all the records?

It gives you the number of the first changed record. Then you may check with GETFLDSTATE() function which field has changed for this particular record.

But there is no way to avoid looping if you want to test all changed records.