Does my company allow sales of shares?

Each company is different. The answer is usually found in your stock agreement provided when you were granted shares. Some companies allow open selling of shares, and others have blanket bans. The standard policy allows shareholders to sell shares with a transfer fee paid to the company and a 30-day Right of First Refusal (ROFR) period in which the company may exercise their option to buy the shares from the seller instead of the proposed buyer.