How to modify all occurrence of the extracted variable?

From a webpage response, we are extracting all occurrences of the data.
example: {id:1,ref:001},{id:2,ref:002},{id:3,ref:003}

Now, we have to post the all occurrences but modified (+A) as below :
{id:1,ref:A001},{id:2,ref:A002},{id:3,ref:A003}

How to modify all occurrence of the extracted variable?