The act of replacing one thing with another

transfer, substitution, replacement, change, supplanting, rearrangement, shift, revision, resale, transposition, interchange, trade-off, commutation, switch, shuffle, shuffling, castling, sleight-of-hand, hocus-pocus.

The act of giving and receiving reciprocally

reciprocity, reciprocation, barter, trade, swap, correspondence, interrelation, interdependence, cross-fire, buying and selling, swapping, negotiation, transaction, commerce, interchange, dialogue, tit for tat*, give and take*. *

A substitution

change, shift, swap, trade, interchange, replacing, shuffle, reciprocation, supplanting, replacement, switch, supplantment, commutation, trade-off.

A place where exchanges take place

market, clearinghouse, stock exchange, bourse; see market 1.

To replace one thing with another

substitute, transfer, replace, invert, give in exchange, commute, pass to, give over, reverse, provide a substitute, provide a replacement, transpose, shuffle, shift, switch, swap, revise, rearrange, change, interchange, trade off, cash in, return, transmute, reset, change hands, castle, borrow from Peter to pay Paul*, swap horses in the middle of the stream*.

To give and receive reciprocally

reciprocate, barter, trade, swap, alternate, interact, interchange, bandy, trade off, correspond, buy and sell, transact, return the compliment, make an exchange.