SUBSTITUTE Replaces existing text with new text in a text string.
Syntax
SUBSTITUTE(text, old_text, new_text, instance_num)
Parameters
text – The text in which you want to substitute characters, or a reference to a column containing text.
old_text The existing text that you want to replace.
new_text The text you want to replace old_text with.
instance_num (optional) The occurrence of old_text you want to replace. If omitted, every instance of old_text is replaced
Return Value
A string of text.
Reference Data
https://docs.microsoft.com/en-us/dax/dax-function-reference