Assigning D patta

Local laws apply to the facts posted by you.

It will be better to consult a local prudent lawyer for appreciation of facts/ documents and professional advise/ necessary proceeding

better to consult local lawyer will be helpful to solve the issues

What exactly you mean by "Assignment".  Yes. D patta can be transferred legally after a prescribed period through a valid sale or gift deed.  You can file RTI Application to District Collector and can seek clarification for all the laid down norms for all types of transfers and can also get certified copies of Government orders.  First, make a google search to find out relevant information with key words "Assignment of D. Patta in Andhra Pradesh"

(2A) No assignee shall transfer any assigned house site, and no person shall acquire any assigned house site, either by purchase, gift, lease, mortgage, exchange or otherwise, till completion of the period of 20 years from the date of assignment.

(2A) No assignee shall transfer any assigned house site, and no person shall acquire any assigned house site, either by purchase, gift, lease, mortgage, exchange or otherwise, till completion of the period of 20 years from the date of assignment.

Any transfer or acquisition made in contravention of the provision of sub-section (1) of sub-section (2) [or subsection (2-A)] shall be deemed to be null and void.

For the purposes of this section, where any assigned land is in possession of a person, other than the original assignee or his legal heir, it shall be presumed, until the contrary is proved, that there is a contravention of the provisions  of law.