In dealing with conflict, it is important to approach it in a(n):

In dealing with conflict, it is important to approach it in a cooperative manner.
You need to work and think hard when it comes to resolving a problem and dealing with conflict. You want to deal with the problem as smoothly as possible, and not be destructive, competitive, or ambivalent about it, because that way, the conflict won't be solved or it might but it will return very fast.

productive most commonly means: achieving or producing a significant amount or result.

explanation:

productive can also mean:

producing or giving rise torelating to or engaged in the production of goods, crops, or other commodities.

these depend on how the word productive is used. most likely productive will mean   achieving or producing a significant amount or result.