There are three ways you can sell, any time you want:
Sell to other investors on Fractional with a 5% transfer fee.
Sell back to Fractional at a maximum of 80% of fair market value at that time. For example, if you owned 25% of a property with a FMV of $200,000, you can exit at $200,000 x 25% x 80% = $40,000.
Sell the entire property upon approval from co-owners.