Greetings,
If you have a large programming statement, you can use 「F8」 to update all the variables within a math statement.
Unfortanelty, the search/replace function you are asking about is not part of default interface.
May this be of Good Help;
⚜ Kenny Lemens, P.E. ᵂᴵ
"No matter where you go, there you are." -Buckaroo BanzaiHotkeys: https://en.smath.com/forum/resource.ashx?a=45771&b=2