To surrender means to allow the situation to be just as it is, to let go of any sense that the universe is out of whack because what is happening may not be to our liking. As a spiritual practice, it is not a synonym for resignation or giving up. Surrender means to stop struggling, because struggle never really helps.
Of course, if there is action we can take in order to reduce the suffering of ourselves or others, we will take it. But far more often than we imagine, action taken out of desperation only makes matters worse. The Titanic sunk because action was taken. By steering hard to the side, the iceberg scraped along the length of the ship, flooding a critical number of compartments and dooming the vessel. A head on collision would have done damage and cost some lives, but it would not have become the all out disaster that taking action caused.
No matter what the difficulty, we can learn to relax, soften, and open into the situation, surrendering to the reality of it and allowing any action taken to flow from this place.