The Swap action within the link maintenance tool allows you to exchange the linkage of two connections from one base object. It combines the activity of two disconnects followed by two connects that you would have to do otherwise.
You need to have two link objects of regular link types (LUL, LUR, LDL, LDR) of the same base object with valid values, which are pointing back from the destination objects with links to our base object. One of the link value is allowed to be NULL The order in which the link spots #1 and #2 in the upper half are populated is irrelevant.
This action is reversible by just hitting the swap action button again.
One example is swapping the trailing branches (blocks B78 and B79) of a switch (W25) shown here:
=== SWAP ===
The linkages from B78 and B79 back to W25 do not change and are not shown here.
Another example to swap the left end and right end (C169 and C171) of a block (B372) like here:
=== SWAP ===
Again, linkages from C169 and C171 to this block do not change.