There are different kinds of withdrawals depending on the topic we are talking about, but since this topic falls under the part of Map and Geography Trivia (3P071 Volume 3) which may or may not talk about security forces, we can say that the two types of withdrawal are assisted and unassisted. A withdrawal is defined as a planned operation in which a force disengages from an enemy force and it may happen under enemy pressure.
Withdrawals are done especially when a situation requires fast action from the commander so that he can save his command from further disaster. As the name implies, a withdrawal is considered as assisted if the command receives assistance while they retreat from the enemy force. An unassisted withdrawal happens when the command withdraw from the enemy force without any assistance from any other chain of command.