It would be a misguidance if A is advised to withdraw the suit.

If A withdraws the suit then he may not have any ground to claim his property from the builder.

The builder should have executed the registered sale deed in favor A long ago, whereas due to some reasons this could happen till now hence A as approached court with  suit for declaration of his title based on the sale agreement and also on payment of the full sale consideration amount to the builder.

Hence it may not be advisable for A to withdraw the suit because he will be never be able to claim rights or interest over this property and he would miserably fail to fulfill his commitment to X in this regard

He can take possession unless it's not challenged by the affected party 

Agreement of sale is not a sale till sale deed is registered .

You are going through a wrong process. 

Now you need specific order from court for registration in favour of X by B otherwise  B can not legally do it. You have complicated the entire process which is legally wrong also since without registration of sale deed in your favour you can not mortgage it to other. 

X as on date can not take the possession of the property since he is not a party to the sale transaction .

Without specific court order you can not do anything now. 

1) A can withdraw suit against builder 

2) X can take possession of flat as per court decree 

3) please clarify why builder is not willing to execute sale deed in favour of X 

4) A can pay builder transfer charges and tripartite  agreement can be executed between builder A and X 

Mr A can file a civil suit as well for the specic performance of contract and and interim injuction to restrict the builder from alienating the property or to sell it to some one else so as to defeat case. 

- Herein , till date the actual owner of the said flat is Mr.B -builder , and no one execpt him , has right to transfer the owner ship /sell the said flat as per law , including Mr.A or Mr.X. 

- Agreement to Sale in favour of Mr A. and attached receipt of full sale-consideration therewith , is not a title deed or sale deed , which is required to claim ownership. 

- Mr. A , handover the said documents in favour of Mr X , to clear his dues , and not for selling the flat . 

- Ahmednagar District court has only granted to withdraw the case of RCS , and not to execute the sale deed in favour of Mr. X, and further there is no relation between Mr B and Mr X legally. 

- Since, the case is pending for adjucation before other Court , hence Mr X cannot take possession legally , on the gound of first court order, but he can be party in the said suit. 

- If Mr.A will withdraw the case from the other court , then the ownership will remain with Mr.X. 

- Police cannot assist you for the same , because your suggestion is against the law. 

Good luck and dont forget to rating Positivley. 

No your suggestion is not at all good. 

Because Ahmednagar court have not order for taking possession of flat but the suit was withdrawn without any relief from court on ground of settlement between parties. 

The suit of mr A should be filed for specific performance of contract against builder. 

So he should file application for amendment of plaint to change ground of suit.