How to replace property name in History template comment column

Hi Team,

I have an template in that one property name is abc_xyz and label is  "abc xyz". On viewing history of particular item at Item level I am getting as "abc_xyz:PQR".

I want to replace property name as "abc xyz" while viewing history.

Current History View

    When   |            Who          |  Action   | Comment

4/11/2015 | Innovator Admin  |  Update | abc_xyz: "PQR"

Required History View

    When   |            Who          |  Action   | Comment

4/11/2015 | Innovator Admin  |  Update | abc xyz: "PQR"

Can any one please guid me on this how can i achieve this?