Ticket Transction custom field scrip

Hi All,

I am running RT 3.4.5 pgsql + Ubuntu as the backend.

I have created a custom field “AssistedBy” as a Custom Fields for Ticket Transactions and type “Select one value” and applies to ticket transactions.

I have created one more Custom field “Assistance” (Applicable to Tickets ).

I would like to know how to write a scrip which will update Assisatnce( In tickets ) based on the value of AssistedBy ( Transactions ).

For Eg:-

If AssistedBy(Transcation CF) = manju on resolve it should update Assistance(Ticket CF) = manju

Hope I am clear on my question. I would greatly appreciate any input from you guys.

Thanks in advance