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.
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
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.