Joint tenant

The answer to your question is definitely no.

This is because joint tenants are considered as one entity in relation to their title and ownership (in layman terms) to the property, and both of them must consent to any transfer or disposal of the property.

Joint Tenants =
意思，即係 a 及b君為物業之共同擁有人，假若a加先逝世，物業之業權會自動轉左比b君，亦俗稱長命契。
如要賣樓必須要兩位業主出黎簽文件，如臨時買賣合約、正式買賣合約、樓契。

it should be to have both agreement on 2 party for tranfer or sell the property. if any of them not in hk , he/she should have signed an paper agreement on this issue for the selling process.and permit someone to present it while signing any related document.