This is what I've done in the past, I don't know if it's applicable to your project. I had a video with text in which the background was stationary, and the text changed throughout a period of frames. I exported a single frame with the background and text, then used another program to insert the text I wanted over the undesired text on that frame. This works well if your background is simple. For more complicated backgrounds, you will have to be a bit more creative.
I created a series of stills with different text overlays that I sequenced into Premiere. A quick and dirty is to put the original video on 1B track, and your imported stills on video track 1A. Since 1A has precedence, it saves time of segmenting the original video clip. I arranged the stills according to my desired timeline, and the resulting video had the effect I wanted.
A bit tedious, there may be more efficient ways.