180 days is a long time.
Before you relist you need to look at the possible reasons for such a long time on the market and adjust the new listing to be more attractive to buyers or you will be in this same situation.
Have your agent pull the comps so you can get an idea for changes.
Real estate is all about 'location, location, location'; but honestly, being over-priced is usually the top factor a home doesn't sell.
Besides price, look at the other things you have control over: how clean is the home, does it smell (especially if you have pets or smoke), how is the yard since curb appeal is so important, are there any repairs, consider staging the home, etc...