title: Change legend names in ggplot2 without changing function colors
body: <p>I have the following code:</p>
  
  <pre><code>library(tidyverse)
  data1 %&gt;% 
  gather(key, value) %&gt;% 
  ggplot(aes(value, color=key)) + 
    stat_ecdf(size=0.8) + xlim(-4.5,4.5) + 
    labs(x = "t(α)", y = "Probability", color="Legend", labels=c("Actual","Simulation"))
  </code></pre>
  
  <p>which produces the following output: </p>
  
  <p><img src="https://i.stack.imgur.com/h6QFM.png" alt="CDF plot"></p>
  
  <p>My problem is that I would like to keep the colors from the current ggplot theme (theme_gray), but at the same time be able to manually set the legend/label names. I am aware of a similar <a href="https://stackoverflow.com/questions/13848036/changing-legend-names-without-changing-colors-in-ggplot2">question</a> written by a Mr. Taylor. However, the answer marked as most helpful are defining the colors manually. In this project, I am going to have plots with multiple functions, hence I would like ggplot to just use its build-in theme's colors in order to keep the colors consistent throughout the project.</p>
  
  <p>I have tried versions of </p>
  
  <pre><code>scale_colour_manual(values=c("color1","color2"), labels=c("Label1","Label2")
  </code></pre>
  
  <p>but I am unable to just name the legends without also having to define colors.</p>
  
  <p>Thank you in advance for any help!</p>