關於房屋買賣中的determination of agreement

同賣方簽的合約包括買方有30天的due diligence period, after due diligence period賣方就keep2.5萬的earnest money，賣方可以免費住兩個月after settlement.

在due diligence period, 買方要求賣方簽一個agreement 包括賣方要簽lease with new owner and leave $1000 security deposit. 賣方拒絕，事情就一直拖下來，現在過了30天的due diligence period, 賣方要keep earnest money.

buyer's agent 說合約有一句話the agreement of sale is pending on the buyer receiving the seller property disclosure. 買方從沒有收到過賣方的property disclosure. 想以此為由walk away. agent 說要雙方簽一個determination of agreement。 買方擔心的是根據那句話這個agreement of sale 是無效的。 如果簽了determination of agreement，會不會就變成買方default承認agreement of sale是有效的，才有之後的determination. 謝謝指教！