I have a dataset that contains a large number of customer IDs, a previous customer ID and a variable that represents the first acquisition date. Occasionally the customer ID is changed  and the value of previous customer ID is updated accordingly. This can happen multiple times and unfortunately, each time this happens the first acquisition date is updated to the date of the ID change and is not carried over.    Current Dataset Example:            Customer_ID           Previous_Customer_ID           First_Acquisition_Date            A103420830                                                             01JAN2014            B100453820            A103420830                            01JAN2015            C293099201            B100453820                            01JAN2016   I need to retain the true first date of acquisition against these ID changes but I am having some difficulties dealing with more than one ID change. Any help would be appreciated. ... View more