Update in-flight processes to use updated rules

Question

We have just pushed a package/delta of an application, now the in flight/old instances are failing as the rule which is being used in the process model is changed and the in-flight old processes are referring to the older rule which expects one less parameter... So it throws the error that the rule is expecting 3 parameters, instead only 2 passed.... What is the best way to resolve these kinda existence instances? 
 OriginalPostID-140948 
 OriginalPostID-140948

Conor Cahill · Accepted Answer

if you call rules using parameter keywords then it won't throw that error rule!test(param1: [value], param2: [value]) will work even if rule!test has 3 parameters. Any parameters not given a value will be null within the rule, so you would need to be able to account for some of them being null in the form or rule.