Skype has the following in their help section
/find [text]
Finds specific text in a chat. For example, /find Lucien will return the first instance of the word "Lucien" in the chat.
I have not able to find one for s/ but it works.
so far I was able to try
s/old/new/
s/old and new/new and new/
Can anyone describe what are the features that are available to me in the s/ and /find commands ? For example: Can I replace in multiple lines ?