The shares (or other securities) that you invested in will most likely, not have a ready market that would allow you to sell unless the particular company you invested in has entered into or will enter into an agreement with say a secondary market provider or others analogous to that.
The disclosure document will set-out the exit strategy for enterprises. For example, the directors may consider that there is an opportunity for what is known as a “trade sale” or to list the company on a stock exchange such as the ASX. This may provide you with an opportunity to exit and cash in your investment.
There may be particular rules regarding selling or otherwise disposing of your shares and these will usually be set-out in the disclosure document and/or the company’s constitution. As mentioned previously you should always seek professional advice.