How to re-trigger Release Strategy which has already been released in SAP?

The Issue

I want to enable a functionality to release the PR after changing the existing one(Which is already released). Please let me know the configs to be done for enabling this.

The Solution

Regarding the issue of re-releasing a PR/PO after it has been released and then subsequently changed, please follow the steps below.
1) SPRO --> MM --> Purchasing --> PR --> Release Procedure --> Procedure with classification --> Set up procedure with classification --> Release Indicator
2) Double click on the indicator that you use for the Release (Most of the time, it would be 2 - RFQ/purchase order)
3) Set the changeabil to 4 (Changeable, new release in case of new release strat or val change)

With the setting above, it will re-trigger the release strategy. It can be retriggering the same Release Strategy or a different one, depending on the changes that you have made to PR.

However, if the change is a decrease in Value, it will not re-trigger the release. Only an increase in val change will it trigger a new release strategy.
Currently, there is no way to re-trigger release strategy when there is a change in value (decrease).

Source: http://forums.sdn.sap.com/thread.jspa?threadID=1657203&messageID=8967611#8967611