Charles
I think we may have a terminology issue here. A Report does not change data, it only diplays data. If the Report is showing data you think is wrong then chances are the Report's format is incorrect.
On the other hand it is possible that you want to want to have Agent Details in the Agent table change without changing Agent Details that are stored with another record (say Agent Sales). For example the Agent's Base Commission may be stored in the Agent Table. However the Commission rate is subject to change throughout the year. If you want to print a Report that acurately shows the Agent's commission rate through time, then you must store is in the Agent Sales table as well. Probably a bad example, but I hope you see what I mean.
Chris