If you want to leave the trade, you will have to sell Euros and buy back US Dollars. You will be hoping that you were right in your guess and that the exchange rate for EU/USD has actually risen, which means that you will get more Euros back than when you bought them, which is how you will make a profit.
These days just about every forex broker is claiming to have the tightest spreads in the industry. But marketing does have the ability to be deceiving. The topic of spreads in the forex spot market is very complicated and often not easy to understand. However, nothing affects your trading profitability more.
First of all in order to understand the spread, you need to know what it is. A spread is the difference between the ask price (the price you buy at) and the bid price (the price you sell at) that is quoted in the pips. If the quote between EUR/USD at a given moment is 1.2222/4, then the spread equals 2 pips. If the quote is 1.22225/40, then the spread is going to equal 1.5 pips.
Brokers generally don’t earn the full spread, especially when they hedge client positions. The spread helps to compensate for the market maker for taking on risk from the time it starts a client trade to when the broker's net exposure is hedged (which could possibly be at a different price).
Spreads are important because they affect the return on your trading strategy in a big way. As a trader, your sole interest is buying low and selling high (like futures and commodities trading). Wider spreads means buying higher and having to sell lower. A half-pip lower spread doesn't necessarily sound like much, but it can easily mean the difference between a profitable trading strategy and one that isn’t profitable.
The tighter the spread is the better things are going to be for you. However tight spreads are only meaningful when they are paired up with good execution. Quality of execution will decide whether you actually receive tight spreads. A good example of this is when your screen shows a tight spread, but your trade is filled a few pips to your disadvantage or is mysteriously rejected.