Is there specific text you can search for to delimit the text that you want to retain?
See Microsoft's
T-SQL string functions.
You can use
CharIndex or
PatIndex to find a start/end point (
Reverse if you need to search backward from the end of the string) and
Left/
Right/
Substring to extract the text you want to retain.
[Edit to add:]
Suggestion: If you're not sure how to make it work, provide an example of the string you're trying to extract from and identify what text you're trying to extract from it.