Options can be executed any time during the ICO. During the first day of ICO tokens are sold to option holders only, and option holders are guaranteed to be able to purchase their coins. Starting from the second day of ICO tokens are available for purchase to everybody. However, option holders still can execute their options if there are enough tokens left in the total pool.
If a person changes his mind, he can execute the option partially or not execute it at all. Let’s take the example from the article when a person bought option for 5$ and reserved 130GVT. Instead of paying remaining 95$ he can pay, for example, 47.5$ and will get 65GVT.
However, the price of the option (5$) is non-refundable. A person won’t get 2.5$ back in the previous example.
@genesisvision - concept is interesting, to say the least. I'm reasonably familiar with the concept of options - you have a first party (buyer) that purchases a contract from a second party (seller) with the right (but not an obligation, like you say) for the buyer to purchase from the seller at a fixed price before a given expiry date. However, what I'm not clear on here is who acts as the second party in your proposition above - is it GenesisVision (because they have negotiated a deal with the ICO - that's my impression?) or is it the ICO themselves? Thanks.
The difference with traditional option concept here is that you don't make any contract with some company, the whole process is controled by the smart contract, providing digital guarantee for the option execution. So we can say that in this case a second party is a Genesis Vision's ICO smart contract. And the underlying asset of option in this case is Genesis Vision's ICO Token - GVT.
Basically, this concept can be implemented for any ICO, for any particular ICO token.