Statement end date

SUGGESTED

I have two questions please ~ i understand that to do a reset on the bank reconciliation it tells me to back up as I will lose all my data.  It just does not tell me how much of the data is lost.  Is it from the initial setup for the account?  Is it only for the current year?  Can someone delineate?  I have 5 accounts that I reconcile.  I need clarification please.   

Question # 2.  I did a bank reconciliation for October.  Statement end date was set as October 31.  Starting with November reconciliation it is showing the statement start date as October 29 with outstanding transactions showing which previously cleared through the 31st.  Why? and how to correct this since October was posted?

Everything I've read indicates you can't change anything once it's posted and the reset is the only answer.  Am I looking at redoing reconciliations for the entire year if I choose to reset?  

Does the reset remove the information in my GL as well?

PS/ Back up has been done - and the Report printed off for the month of October only.