Workbook Sharing and Text Splitting

First off.. hello to everyone! i jus joined this forum and hope to learn a lot from everyone here...

now.. to my issue..

Whenever i try to share a workbook (saved on a network path), inspite of checking the option "Allow changes by more than one user at the same time", other users still get a read only prompt when they try to open the file if its currently being edited by me. How do i allow multiple users to make changes simultaneously to the workbook?

Question 2... If i have the text "ICICI Bank" in cell A1 and "Deutsche Bank" in cell A2, how do i split the words and make them appear below one another in the same cell (kind of like an Alt + Enter, only I am looking for a automated way of doing this)...

Any help will be much appreciated...