Summary:
To prevent "SLIDING" (repeatedly advancing a RV/campsite reservation beyond the 90 day window) you cannot make changes to your reservation until your departure date falls within 90 days of today's date.
There is a non-refundable change fee of $5.00 per change.
If a change to arrival date is made less than 72 hours before 4 PM of the scheduled arrival date, up to two night's camping fee will be forfeited. Any remaining camping fees will be refunded.
There is an additional, non-refundable, change fee equal to 50% of days removed from any reservation that is changed to advance its arrival by more than one day from the original reservation arrival date.
Details:
For example, if someone has an original reservation for 21 days beginning on June 18 and ending on July 9, and they call to change that reservation, once July 9 is within 90 days, to have their reservation now start on June 30, that person will be charged based on the following algorithm:
Cost Per Day = Original Cost / Total Days = p
Days Reduced From Original Total = r
Sliding Change Fee = p * r * 50% = n
Plus Standard Change Fee = n + $5 = TOTAL CHANGE FEE
EXAMPLE
Original Cost = 904.05
Total Days = 21
Cost Per Day = 904.05 / 21 = 43.05
Days Reduced From Original Total = 12
Sliding Change Fee = 43.05 * 12 * 50% = 258.30
Plus Standard Change Fee = 258.30 + 5 = $263.30
Just to reiterate, all change fees are non-refundable, even if the original reservation is subsequently cancelled.