Often, but unfortunately not always, manual changes can be done without external assistance.

Many catalog software vendors offer their customers the possibility of doing this part of the revisions themselves. Yet, there are also cases where an external specialist must be hired. The reason for his is that the way the hotspot and link information is created and stored is not always understood by the customer. 

Please, make sure that you have full access to this part of the process. In the best cases, this part of the revision can be fully automated, which has a considerable effect on the run-time cost of the catalog.