https://community.appian.com/discussions/f/process/12319/issue-in-changing-data-type-of-a-process-variable-in-17-2-version-of-appianHi all, I have a process model with one process variable of &quot;Number decimal&quot; type which is also passed by reference in all the other sub processes. As per the new requirement I need to update the data type of the same process variable to &quot;Text&quot; typeen-USTelligent Community 12https://community.appian.com/thread/54521?ContentTypeID=1Fri, 27 Apr 2018 12:41:49 GMTd3a83456-d57b-489c-a84c-4e8267bb592a:28adb02d-ff28-4e9e-b5ff-268f7b71c9dbchanduAll the New Instances will take the last published version of the Process Model. So changing the data type of a process variable is failed in your case. We have two Options.<br /> 1. Create an Utility tool to Upgrade the Old Instances.<br /> 2. Do inflight Modifications for all the Old Instances.(Need to go the Process Instance and cancel the SubProcess and restart a New one. In this case also some times the New Instances will not pick since you need to restart the parent Process as well.<div style="clear:both;"></div>https://community.appian.com/thread/54519?ContentTypeID=1Fri, 27 Apr 2018 12:20:37 GMTd3a83456-d57b-489c-a84c-4e8267bb592a:b6a65a59-b68f-4fc6-b8ef-03ba589ed3easantoshd378<p>Hi amitas,<br /> <br /> Go through the link for upgrading the In-flight process models.<br /> <a href="https://docs.appian.com/suite/help/18.1/Process_Upgrade.html">docs.appian.com/.../Process_Upgrade.html</a></p><div style="clear:both;"></div>