You abd your siblings can execute gift deed or relinquishment deed to transfer or relinquish your share in property in name of mother

2) it should be duly stamped and registered

Hi , all the legal heirs ( you and elder bother/ sister ) can execute a gift deed in favour of your mother ..

mere NOC is not sufficient

Gift deed or relinquishment deed has to executed by the children

Three of you could gift your share each to your mother. This way the whole of the shop goes to her and she may get her name mutated.

Second option is to execute a relinquishments deed.

Deed of gift is the most suitable option for you.

Mere noc doesn't relinquish share of all joint title holders in the property.

So if all the legal heirs wish to make any of you the sole owner of the property making a registered deed of gift or deed of release is only option.

All the other legal heirs of your deceased father may jointly execute a registered release deed relinquishing your rights in favor of your mother in respect of this shop property.

Then your mother will become sole owner of this property.

The current counsel has asked the three of us (children) to only prepare one NOC for each of us declaring that we dont have any objection. If we go for an NOC and not for a gift deed, could there be some complications in future ?

The NOC is not valid and not a proper document to transfer the property to your mother's name.

You all can jointly execute a registered release deed relinquishing your rights in favor your mother.

Gift deed will not be applicable to this situation.

Giving NOC at this stage ill suffice your purpose without any legal complications in future.

Regards