The agreement between the buyer and seller is referred to in legal terms as a conditional sales contract. Quite often a down payment is required.

卖方与买方之间的这一协议，从法律的角度就是一种有条件合同，往往需先支付一笔定金。

youdao

An Agreement of Purchase and Sale for a particular property which is conditional (becomes binding) upon the failure of another Agreement for the same property.

某物业的买卖协议，只有在相同物业的另外一个协议作废后才生效。

youdao

The workers' agreement to return to work was conditional on the management increasing their wages.

工人们同意复工，但条件是资方必须增加他们的工资。

youdao

There was a conditional agreement: yes, Norway should manage this oil risk but it's politically difficult and that's the problem-- is that we're not able to do our optimal management.

他们在一定程度上同意我的观点：,是的，挪威应该设法解决石油的风险,但这在政治上很困难,其问题在于-,挪威无法做到最优的管理。

耶鲁公开课 - 金融市场课程节选

SingTel just announced that he had reached a "non-binding conditional agreement" to take 14.5% of Time Engineering, 20% of Time dotCom and 20% of Time's new Internet Service Provider, Time Online.

CNN: Business: SingTel Wins One At Last

The joint venture will also purchase a 25% interest in the Whitgift Centre, following completion of Hammerson's conditional acquisition agreement with Royal London, which had a 155-year head lease on it.

BBC: Croydon shopping centres in ?1bn regeneration plan

In addition, the DISH Proposal would require Clearwire to terminate the note purchase agreement under which Sprint has agreed to provide interim financing to Clearwire and is conditional upon the consummation of the spectrum purchase and Clearwire being in compliance with the commercial agreement (both as described above).

FORBES: Fat Lady Still Not Singing In the Sprint Acquisition of Clearwire