You can modify source content of a file, and since WordFast Pro stores the original source content in a TXLF file, you can restored the original at any time. Commit the edited source segments to update the TM.
To edit source segments:
In TXLF Editor, select a source segment.
On the Edit tab, click Edit Source.
Edit the source content as required, then click outside the segment.
The source segment is saved and the icon displays in the Status column.
To revert to the original source, click Revert Source.
icon displays in the 