How to ask a girl out n at d same time stay friends in case it dosent wrk lke u planed?

If you are already looking at this like it could fail then do not bother because it will. There is no way the relationship will be able to go back to what it was. Life never works that way except in very rare cases. You just have to decide if it is worth the risk or not. One thing you could try is to talk to her and let her know your thoughts.