How to change Part/Document default revision from alpha to numeric

Hi All,

I am newbie, using the Aras Innovator. 

I found the default revision set as alpha. I tried to change it to numeric but causing errors when I try change it back to alpha as all the item created has been used as alpha previously. 

Instead of replacing the default "revision" setting from A B C D... to 1 2 3 4.....,  I guess it can be solved by creating a new "revision1" rule with numeric setting.

Then I need to write few codes to employ it only to the part/document type property, however I am not sure how to do it correctly here. 

Could anyone teach me here?

I found a post that exactly same happen to me. 

--> https://community.aras.com/f/archive/2034/developers-forum---error-comes-when-i-change-default-revision-of-aras-innovator 

Highly appreciate your help!

Br, Magga