Flat Ownership

'A' and 'B' co - owner, B wants to give rights to property only after death to the 'A' / heirs of 'A'. 1) Conditional settlement deed - What exactly is this and will this serve the purpose. 2) Gift Deed - My heirs of 'A' remove 'B' demise of 'A' - is that correct ? is there any Tax implication on Property Gift 3) Relinquishment deed - Will this work in my case, can there be a condition added that the Relinquishment should happen only after demise of 'B'