Depending on which word in the 'Find line' you want to change, you may be able to call a common script and stipulate different script parameters. In your common script concatenate Get(ScriptParameter) in your line (e.g. "…" & Get(ScriptParameter) & "…" )
And it sounds like you are using Perform Find [Restore]
There's another way to do this that uses Perform Find  -- no criteria is stored in the script step.
Instead, the script enters find mode and uses a series of set field steps to specify the criteria. This opens the door to using a script parameter, a global variable or a global field as a way to specify that "line that needs to change".
Here's a thread with a number of scripted find examples that use Set Field to specify find criteria: Scripted Find Examples
Jade and PhilModjunk--
Thanks for your responses. I have not had a chance to try either one, as the project I was working on has been shelved, at least temporarily. If it gets reinstated, you can be sure that I'll follow through and let you know how things are going.