NINTEX Forms - Replace function

I am moving from INFOPATH forms to NINTEX forms and have run into the following issue:

I  need to change ' single quote to ` back quote when user enters data in text field in Nintex form.

In INFOPATH, I used translate 

I have tried fn-Replace in NINTEX form but it does not work. 

I have tried with quotes around  "'", "`"  as well.

Thank you.