Only on rare occasions will you ever need to do an appraisal on a timeshare. Perhaps in an instance for special financing needs or possibly giving as a gift or even an estate valuation purpose.
If is does occur, consider asking the timeshare developer you bought it from or perhaps other timeshare owner who they might have used and would recommend.
However keep in mind that the method of appraising timeshares might not be accurate due to the range of transaction prices and may not be useful except as a rough estimate value.
For financing purposes – you could use a local, licensed real estate appraiser that is a associated with the Appraisal Institute or an Independent Fee Appraiser (IFA).
If you are just interested in placing a value on your timeshare in order to file a claim, report or whatever a "broker's" opinion may be sufficient.