Use this method to update the value of one variable in a
business process definition (BPD) instance. Only the system or process application
administrator can run this method.
Note: This API cannot be used to update subprocess or linked process variables. To update these variables, use the Process Inspector in IBM Process Designer or the REST API "Update Instance All Variables".
Note: The use of the term "items" as a variable name is not recommended because it is a reserved word that is used to denote lists of objects in a process. However, if the term has already been used as a variable name, the value can still be updated. See the "Request content" section for an example.
Note: When you are updating a variable of complex data type, the whole variable is updated exactly as specified. Therefore, you must specify all the fields to be set for the complex data type variable. Variable fields that are not specified are treated as not set and their existing values are overwritten.