New wsdl or reverting?

hi,

I am new to PI.
In my current prj, client told me to remove some fields in wsdl.
I got the xsd and removed the fields and i generated the wsdl.
Now clients wants the previous wsdl[they want those fields].
Now do I need to change the xsd and generate the wsdl or
In history Can I choose the previous state.

In the history of that obj shall If I choose previous state, does it work fine?
Please suggest me.

BR,
Avinash M