How common is it to ask for revisions if you have only read the first three chapters? I have just gotten such a request from a very reputable agent, but am in a quandary on quite what to do and how to respond. She also suggested a book for me to read though I am not a newbie and have been writing for a very long time. One of her suggestions would be quite a structural change-- and she has not read the entire manuscript. However, representation by this agency would be quite a boon. So--- my dilemma. Thoughts?