从条件状语从句变为目的状语从句,首先应该去掉if
 
然后,如果是原句直接改过来应该是
You take every chance you get so that you can be a happy and lucky person.
但是这样行文比较怪,可以稍加修饰
You (should) take every chance you get so that you can be a happy and lucky person.
括号中的should还可换为ought to/are to/are supposed to/'d better等