[AUCTeX] Any key combination to delete a macro or/and an environment?

[Adam Johnson]

Hello,

I couldn't find the answer from the AUCTeX menu.  I'm just curious  whether 
there're any key combinations to delete/replace a macro? (I know there're 
keys to delete/replace a font, which is very useful.)

For example, currently, if I want to change some (but not all) $\bar{A}$ to 
$\tilde{A}$, I need delete \bar{} first and then add \tilde{} around "A", 
which is not convenient.  Sometimes, maybe I need replace all $\bar{A}$ to 
$A$, then I need delete \bar{} manually.  My idea is to use some key 
combination to replace or delete \bar{}. (If {} exists for this macro, also 
delete this pair if necessary.)

Also any key to delete an environment? (I know the key to replace an 
environment.)

Why the short cut of the menu command: Ref/View Crossref only shows as 
(C-c )?

Thanks a lot.

BTW: I'm using AUCTeX  w/ preview-latex11.81
                        MikTeX 2.4
                        CVS Emacs 22.0.50.1
                        Windows XP.
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Best Regards,
Adam