Replacing a specific char

Could you please let me know how can I replace the last character of any word in my tags, without replacing the similar characters inside the word?
For example, change the word ababa to ababc.
Thanks in advance

Create an action of the type "Replace with regular expression"
Type in as search string: a$
Type in as replace string: c

Thanks a lot. Very kind of you.
What if there are more than one word?
Example : ababa cdcda efefa.... to ababc cdcdc efefc

a second action would be necessary
search a\s
replace with c

I cannot think of any string where that would make sense.

Great !!! It works. Thanks