If Purchase order number skips

Hai Friends,

Iam to new to Navision, Help me

If I Skip a purchase order no then i want that Skipped no i will change in the number series
then i will do the Order,
then after if i want new order i have to check last purchase order no then i have to change and doing the new order

Is there is any possibility that navision should pick default next number after completion of my skipped purchase order number to continue my new purchase order