Closing Sell:

Closing sell means a sale transaction which offset a long position either wholly or partly. For example, the buyer of a put or call can eliminate his long position by effecting a sale in the same type of contract and this is similar to squaring up of long positions in the equity market. As stated earlier, a long position in call can be closed out by the sale of a call option only and the basic characteristics of both the contracts such as underlying asset, strike price, expiry date etc should be perfectly matched to each other.

As stated earlier, the difference in premium, if any, is the profit/loss of the trader