Conditioning is one of the methods used to address imbalances between supply and demand in supply chains. Under periodic review policy, when the imbalance is beyond certain threshold at conditioning time, some proactive measures could be taken at either demand or supply side or both. For instance, demand could be influenced through pricing (promotion); excessive building blocks could be consumed through component substitution; additional supply could be arranged through flexible contracts. We use System Dynamics to model different conditioning actions. Specifically, corresponding to change of situation, we adopt time period array to realize optimal control along timeline. Some simulation examples are presented to illustrate gradual correction of imbalance situation under different conditioning actions.