My patent application was rejected and I decided not to respond to the office action so the case will go abandoned and all potential patent rights will be lost. My patent lawyer who represented me has a power of attorney and all the paperwork. I have digital copies. Here is the question:in case I want to resurrect the patent or give the idea to somebody else is it enough just to give power of attorney to another lawyer?
There are two separate questions raised in your scenario.
1) In your case, can you resurrect (revive) an abandoned patent application [just by giving power of attorney to another lawyer]?
Normally you cannot revive an intentionally abandoned patent application. You do state that you "decided not to respond" and to let to application go abandoned. Typically this is considered "intentional". The Federal Circuit, however, has allowed for revival due to "mistakes of fact" despite a patentee seemingly deliberately abandoning a patent. Network Signatures v. State Farm (Fed. Cir. 2013).
If a different patent attorney takes over prosecution and seeks to revive the application for "unintentional" abandonment, they have a responsibility to investigate the circumstances of the abandonment. Otherwise, the lack of investigation could be considered inequitable conduct. 3D Medical Imaging Systems v. Visage Imaging, 228 F.Supp.3d 1331 (N.D. Georgia, 2017).
2) In your case, can you "give the idea" to somebody just by giving power of attorney to another lawyer.
If "give the idea" means to assign/transfer the patent application to another party, then no that is not enough. Power of attorney just gives a person power to prosecute your application. It's different than assigning/transferring ownership of the application.
Answering an implied question No it can't be reliably revived - the short answer is that you can't truthfully say that it was unintentional. If you do (untruthfully) say that it was unintentional the USPTO will most likely revive it and may overcome the office action and get an issued patent. But if you, or whomever owns it, ever needs to enforce it, this abandonment/revival will be a weakness that the other side will pounce on to attack the validity of the patent. Another answer mentions Network Signatures v. State Farm (Fed. Cir. 2013) to show that you might avoid getting the patent torn up during litigation. That case was about a missed maintenance fee, not an application abandoned during prosecution and the question was centered on whether or not the new attorney had committed inequitable conduct. I would not count on getting the win that Network Signatures got.
To your explicit question - To give the application to someone else you need to assign it to them. Then they can sign a POA with a practitioner to represent them. Could be the same or a different attorney/agent than you used.
There are other good answers, but they focus on some special cases which almost certainly don't apply to you. So, I wanted to clarify a couple of things:
No one--including the inventor, their friend, the attorneys on file, an assignee, etc.--can revive an abandoned patent application.1 If you allow the application to become abandoned, then the patent rights you wish to transfer to your friend no longer exist.
Your application's status will irrevocably change from "pending" to "abandoned" if 6 months pass and the USPTO hasn't received a valid reply to the Office Action from the inventor/attorney on record. (This 6 months is often divided up; the USPTO typically give you a shortened period of 2-3 months to reply, and then allows you to make use of the full 6-month period if you pay a late fee.) After 6 months, there are no more extensions, and the patent application's status will forever change from "pending" to "abandoned." At that point, no one can revive the patent application (including your friend). All patent rights become forfeited and the invention enters the public domain. Abandoned patent applications can't be resurrected, and no one will ever have patent rights in the US for the specific invention your application described. In general, US laws were created on the principle that intellectual property relinquished to the public domain cannot be reclaimed by any individual.
Whether or not you transfer your patent rights to your friend is inconsequential to the question of irrevocable abandonment. No one can revive the patent once it becomes abandoned. The only way to give away your patent rights is to do so while the application is still pending (before it goes abandoned). Then, your friend must respond to the Office Action within the original 6-month timeline. Transferring the patent rights does not endow extra time to the new owner.
Just to clarify, ideas can't be patented or given away. Here's what you can give away to your friend: your future rights to patent(s) issuing from the pending application. To do this, you have to assign the application to them (which requires filing a form with the USPTO) and their power of attorney must be named (in another USPTO form). At this point, they will have the ability to reply to the outstanding Office Action within the 6-month timeframe.
1There are some rare scenarios where an abandoned patent application can be revived, but they don't seem to apply to your situation. The MPEP/patent rules state that a patent application can only be revived if the application was abandoned unintentionally. You can read about this special case here. If you abandon the application knowingly and then lie to the USPTO, then any patent issuing from the revived application will be invalid and struck down if challenged legally.
I am no expert, and this response is for informational purposes only and not for the purpose of providing legal advice. You should contact your attorney or legal expert to obtain advice with respect to any particular issue or problem. Laws can differ dramatically from country to country, state to state, and technology field to technology field.