Remove text from end of symbol

Hi there, I hope this hasn't been answered elsewhere but I cannot find a solution to the problem I'm having.

It's a fairly simple problem. Essentially, I want to remove some text from a symbol that is obtained from sending a path message to a thispatcher object. This outputs something like:

C:/Users/sxp823/Documents/Max/Octave/Patches

I want to take this symbol and remove the /Patches from the end so that it becomes:

C:/Users/sxp823/Documents/Max/Octave

Then I want to append text to the end so that it finally becomes:

C:/Users/sxp823/Documents/Max/Octave/Response

I've managed to append text using the combine object, but I can't work out how to delete a bit of the text first.

Any ideas?