There is a program that is available that might be the solution you are looking for.  

HomeSmart has teamed up with Knock Home Swap™ eligible homeowners can buy and move into their new home before selling their existing home. Knock Home Swap helps reduce the stress sometimes experienced when selling a house and buying a house at the same time because approved homeowners can make a strong, non-contingent offer on the new house and experience less uncertainty throughout the process.  For more information call Edie Womack 602-620-2936 HOMESMART, REALTOR and Knock Certified Agent