How to put coma in field text

i have got field storing with two or more names saperated with space

fName1 lName1 fName2 lName2 fName3 lName3

i want it to be like

fName1 lName1, fName2 lName2, fName3 lName3

Thanks

Subject: How to put coma in field text

read up on the following

@implode

@replace

@replaceSubstring

List handling

Subject: RE: How to put coma in field text

@implode(@explode(“yourstring”;" “);”,")