Can capital gains be deferred

[Jeffery A Yeingst]

in pennsylvania does a seller receive any benefits in regards to capital gains tax. I was working on an agreement for  a trip lex when the sellers attorney scared the seller into backing out. The owner has the property paid off and I thought the seller could defer the gains till they were paid off.  Thanks for any insight. This would have been our first deal but not looking like it will happen now.