Cashing in on an "in the money" call option?

Suppose you buy a 6-mth call option, and 3 months down the road it is "in the money." If you want to collect your profits, but don't want to buy the shares (because it would mean putting up too much money), how do you get the profit? Someone told me to just sell the call option. But isn't that like writing a call option (which is risky)? Thanks for your feedback.