Customer numerator key ?

[MitchellStarc]

Each customer appear in 12 rows . Each customer has a unique key number that stay forever and never changed. However, the customer ID and the branch can be changed over time. I want to create 2 wanted data sets (one in long structure and second in wide structure). The target is to see the changes of customer id number for each customer key

[PaigeMiller]

Exact same question has been answered at https://communities.sas.com/t5/SAS-Programming/Customer-numerator-key/td-p/788230/jump-to/first-unre...