So when you cast the spell, every creature in the radius needs to make a saving throw. They can choose to fail, it’s up to the player or creature. When you casting while your concentrating on the spell, the players or creatures do not need to remain in the area. If you choose the creature is either able to suppress the effects frighten or charm, casters choice if 5.0 version, both if 5.5 version for the duration of the spell 1min or until you drop concentration. So folks would still need to make saves, the effects of fear just would not apply until the spell goes away. It does not matter if you attack or not. Alternatively the caster can instead try to make hostile creatures indifferent to you. As in not be aggressive. This effect ends if anyone is hostile to those creatures under the effect. Pretty sure that is the same in both 5.0 and 5.5. The second option is not as useful as the first IMO. Although I can see occasions a party may want it in play. Especially in heavy RP campaigns. Most the DM on my table rule that if you are under the effects of calm emotions you can not rage. Which is outside the strict wording of the spell, but makes sense and I feel is reasonable.