How to extract phrase or words from Field

I've created an action which moves performer field to composer field. Works great when the only information is Written By: xxxx:

Example [Performer Field]
Written By: Frank Sinatra

However if the performer field has extra information, I would like to continue to move it to the composer field and run an action to delete everything before Written BY xxxx delete all but composer text. Like this

Performer Field:
Backing Vocals : Michael Cooper, Patricia Nicholas
Engineer : David Houston
Producer, Arranged By : Michael Cooper
Written-By : Carole King

In most cases, Written By: is the last phrase in the fields.

Thanks

for the longer string I would try an action of the type "Guess value"
Source: %performer%
Pattern: %performer% Written by : %composer%

Please note, that the separator in Pattern is taken literally. In your example I found that you once have a space in front of the colon and the other time you don't.
So perhaps you delete the superfluous spaces first.

Got it Thanks. Someone had a similar post sing Artist.

didn't work.

I think the problem is the source is a two tag.

Composer:
Voice [CHANT] : Donald "Satta" Manning
Written By: Michael Cooper

I guess I need an action that says move the first line and, if I may ask, move the remainder up.

To read:

Composer:
Written By: Michael Cooper

I tried an action

%dummy% Written By; as a test but didn't work.

Thanks if you have any suggestions

I think this is because you have a blank between the %dummy% and "Written by". There is none, or is there?

Almost there. Need to revise action.

here's what I have:

Arranged By [HORNS]: Bobby Martin -
Written By: Abraham J. Miller / Jr. / Jeffrey L. Osborne / John T. McGhee

Action:
Format Value: *tried Guess Value, could not get it to work)

%composer%
%dummy% Written By:

works, but it deletes everything after written by:

How can I write it to be

%dummy% Written By: (and whatever comes after Written By)

thanks

I think that everything is already described in post How to extract phrase or words from Field

leads to an action that deletes more or less everything in composer as you do not tell where to save the remaining data. Wasn't that supposed to be COMPOSER? and the source field was PERFORMER?
If the "Import tag-field" action (i.e. "Guess value") does not work then the pattern that you write in "Pattern" does not match the existing data. Here every case of a word and every space character counts.