So I have created some text in Adobe After Effects and applied a mask layer which was in the form of a line path and I have set it as the path for the text.
I successfully animated the text along the path and got it to move smoothly through the animation and now I want to make the text animate in a different way but I'm finding that when I delete the path, it deletes it from the file entirely and not just that point in the video.
How do make it so the path doesn't apply after a certain point in the video without losing all of the previous animation?
You can't delete the path on a text layer and keep any animation of that text layer that uses the path. You can split the layer or you can animate the shape of the path.
I'm not really sure what you are trying to accomplish. Lets say you want the text to follow a curved path then come to a rest with the text on a curved line. Next you want that curved line to become a straight line. The way to do that would be to set keyframes for the mask path and change the curve to a straight line. The text will follow the animated path.
The other thing you may want to do is to animate the path in on a curved path and then have a new line of text come in. You would do that with two layers.
Please explain exactly what you want to do and provide screenshots with the modified properties of your text path revealed so we can see what you are doing. Just select the text layer and press the U key twice, then take a full resolution screenshot and drag it to the reply field in this forum. Maybe we can give you better suggestions if we knew what you were trying to do.