RegEx Help

Hi, I am trying to reformat the from header which is formatted LastName, First Name. I need to change it to FirstName Last Name and get rid of the comma. I'm stuck on the regex, it seems the following should work, its works in Regex coach, but not sure why it wont work on HMR. Thanks in advance.

 

Acme3800-A(test-pattern-rule)# expression ^([A-Za-z]+)(,)(.*)
expression made 0 matches against string
Acme3800-A(test-pattern-rule)# string Jones, Davie
expression made 0 matches against string
Acme3800-A(test-pattern-rule)# show
Pattern Rule:
        Expression : (,)(.*)
        String     : Davie
        Matched    : FALSE
        Matches:

Acme3800-A(test-pattern-rule)#