What is "Standardizing variables" in the procedure of converting First Order Logic to CNF?

Question

What is meant by the step "Standardize variables" in the procedure of converting First Order Logic to CNF? The 6 all steps can be listed as,

1. Elimination of implication
2. Move ¬ inwards
3. Standardize variables
4. Remove existential quantifier (skolemize)
5. Drop universal quantifiers
6. Distribute ∧ over ∨ 

but I can't understand clearly what is standerdizing variables? Can somebody explain with an example?

Answer 1

See in Wiki : CNF - Converting from first-order logic :

2.Standardize variables : For sentences like $(\forall xP(x)) \lor (\exists xQ(x))$ which use the same variable name twice, change the name of one of the variables. This avoids confusion later when dropping quantifiers.