Clients who married made wills and now divorcing - one wants to update Will

Hi - I am not quite sure if I am inputting this into the correct topic. In a nutshell: I have clients who are married, made their mirror wills with me and are now getting divorced. One of them has contacted me advising they would like to now update their Will in view of the pending divorce.

Q) Can I act for one of the couple and if so, is it on a first come first served basis? Should I be obtaining a consent from the other spouse to say they do not have a problem with me acting for one of them.

Any help is much appreciated. My thanks in advance of your answers.