I have the thumbnail set up so that at the end of the tagline text there is a 2 word phrase in capitals followed by three dots, for example, "LEARN MORE...".

Preceding this is a 1 sentence description under the thumbnail title. I'd like the capitalised phrase to appear on it's own line. It's a different phrase for each slide.

Is there any type of line break that can be included in the tagline for the slide?

Could you provide us with a link to your slideshow in order to understand please.

Katia the site is offline whilst I update. Essentially the tagline is a single line entry that appears under the thumbnail title with the image to the left. I want mine to appear like this:

The Title Of Slide
A sentence or two about the slide.
It will span 2 or 3 lines and no more.
Under it is.
A PHRASE....

But it looks like this:

The Title Of Slide
A sentence or two about the slide.
It will span 2 or 3 lines and no more.
Under it is. A PHRASE....

Because the tagline doesn't execute html code so if I put a line break in it just looks like:

The Title Of Slide
A sentence or two about the slide.
It will span 2 or 3 lines and no more.
Under it is. <br/> A PHRASE....

Set the Introtext word limit option at FPSS module parameters to 0.  When this option is enabled all the html tags are being stripped out.