If they want to truly redesign the report you will either have to write an application arround the report designer and then deploy it or they will have to purchase copy of Crystal Reports. Either way they will pay a license fee.
If all they want are small cosmetic changes you may be able to build some of that into the report itself. You can deal with conditional formatting, colors, groupings and sorting. Still if they want more then the only way I know is one of the choices in the first paragraph.
Perhaps I have missed something and in that case hopefully someone on the forum will add those methods as well.
Regards,
John W.