Re: Revoking Joint Tenancy
Is this a joint tenancy with a right of survivorship?
Absent facts you haven't disclosed, most of which would prevent your mother from reconveying the land (e.g., she's not mentally competent), your mother is not going to be able to undo the prior deed. If she wishes to do so, she should consult a real estate lawyer.
The easiest thing for your mother to do, assuming her assets are sufficient, would be to set up an estate plan which conveys other property to the other daughters, in lieu of the share of the real estate she is unable to convey equally.
Re: Revoking Joint Tenancy
Yes, this is a joint tenancy with a right to survivorship. She is quite compitent but easily manipulated by my sister. She basically had no other assets, this property has been in our family for 60 years.
Can she sell the 3 of us the remainder of the land without my sisters signature?
Re: Revoking Joint Tenancy
I don't know Canadian law, but in most US states, such an action would destroy the joint tenancy and leave you three as tenants in common with the other tenant.
You really need a real estate lawyer.