Reciprocity means the pattern will be the same transmitting or
recieving.
There are other things that may not be reciprocal though. The
ionosphere
may change the polarization of the signal. Transmitter and reciever may
have different loading capabilities and the system may change due to
heating
from resistive losses under power.


and let them change, they do not affect the symmetry in the antenna
performance itself.

even when things begin to melt and deform or desolder themselves,
reciprocity still exists even though it is of no use anymore.;-)