calculate columns to group text in another column

[Wendy100]

I am struggling with the text manupliating by dax. here is the sample I have vs I want

Rep can be one name but many times or more than one names. If there is only one name, then return the name one time in column B; if there are more than one names, then return all the names in column B
Thank you for your help in advance.

[Ahmedx]

this is in power Query

[Ahmedx · Accepted solution]

pls try

[Wendy100]

Amazing! It is what I want! Thank you @Ahmedx !