Can I Receive Someone Else's Hair for Hair Transplant?

Just like any other organ transplant, hair can be transplanted from one person to another. This would require the same genetic testing. In fact, it has been done between a bone marrow donor and recipient with success.
I do not know of any hair transplant surgeon who would have the ability to do this. Alternatively you can use your own body hair. However, scalp hair is a better match for the side burns.

The only way to do this would be if you had an identical twin.  Otherwise, it is not possible unless you took powerful immunosuppressive medications which no doctor would give for a cosmetic issue.  What we do is borrow some hair follicles from the back and sides of the scalp which are genetically programmed to never fall out and move them to the areas that need hair.  This can be done for the sideburns.  Good luck.

In order to achieve this. you would have to be given the same harsh immunosuppressive medications that are used in other organ transplants. The benefit to risk ratio is skewed towards too risky for complications. Identical twins could however.

In short, no, you cannot receive someone else's hair for transplant.  While technically possible if one were to go through the process of matching with a donor (like any other organ transplant) and then taking immunosuppresant medications to prevent rejection, this is not really feasible for a hair transplant.
The side effects of the medication and increased costs associated with the testing, medications, and procedure would outweigh the benefits of the procedure.
As others have said, using body hair as a donor area is an option, but is usually not as good of a result as using hair from the sides or back of the head whenever possible.
All the best,

Thank you for your question. Surgical hair restoration transfers
your own hair follicles from a donor site to a recipient site. With the
exception of an identical twin, the transplanted hair cannot derive from
another individual due to the high risk that the transplanted follicular grafts
would be rejected by your immune system.

You can transplant another person's hair as long as the other person is your identical twin.  This has been done successfuly. Otherwise the transplanted hair will be rejected.