Clean up of simple script to correct Session problems

I require someone to quickly look at a script that has been developed for a client, which basically builds an itinerary of dates while they search for holidays. When the visitor has completed their search they then visit a booking page which picks up the stored session information. This has been done using sessions, however I need someone to sort the script to ensure that if the dates fields are empty or the page is refreshed a blank will not be added (as happens now). ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Deliverables must be in ready-to-run condition, as follows (depending on the nature of the deliverables): a) For web sites or other server-side deliverables intended to only ever exist in one place in the Buyer's environment--Deliverables must be installed by the Seller in ready-to-run condition in the Buyer's environment. b) For all others including desktop software or software the buyer intends to distribute: A software installation package that will install the software in ready-to-run condition on the platform(s) specified in this bid request. 3) All deliverables will be considered "work made for hire" under U.S. Copyright law. Buyer will receive exclusive and complete copyrights to all work purchased. (No GPL, GNU, 3rd party components, etc. unless all copyright ramifications are explained AND AGREED TO by the buyer on the site per the coder's Seller Legal Agreement). ## Platform MySQL, PHP 4, Linux, Windows, V4+ browsers