Needs review
Source: Complete Champion

Description: You need not prepare your domain spells in advance.

Prerequisites: Ability to cast 3rd level spells, Access to two or more cleric domains

When preparing your spells for the day, you can leave your domain slots open. You can then choose, when the situation arises, to cast any of the domain spells you could normally have prepared for a given level. However, you are still limited to one domain spell per level per day.

Normal

Clerics must prepare their domain spells before casting.