Currently there is a "update client" action in Servicem8, but Workato doesn't have the action to "update contact".
Apologies for not getting back to you on this sooner. In case you haven't seen it, we now have the feature to update contacts in ServiceM8. Do try it out and let us know if you encounter any issues.
Thanks for making the post. I will definitely forward this to my Team and update you if there is any news :)
Have a great day!
Send us a ticket, we will try our best to assist you with your problem