List of substitution and movement indicators

This is an incomplete list of substitution and movement indicators, covering anything which suggests swapping or movement of letters in a word. Indicators which are suggestive of upwards motion are valid only in down clues (*). =  Substitution and switching of letters   =

Changing the middle one or two letters

 * having a change of heart

Swapping the middle two letters

 * having a heart transplant

Swapping the first and last letters
=  Movement of letters   = =  Spoonerization   = =  Swapping specific letters   = These indicators suggest the changing of all instances of the letter(s) X for the letter(s) Y.
 * changing sides
 * bubbling up*
 * coming up*
 * most prominently
 * rising*
 * to the bottom*
 * to the top*
 * Spooner's
 * swapping tops
 * starts to change
 * X becoming Y
 * X to Y
 * Y for X
 * Y in place of X