Recreate existing function summary block comments

Monodevelop context. Is there a way to easily recreate or update existing function summary block XML that had originally been created by using the triple slash (///)? A classic example is if I had a function like below where the comment block was already intact:

 /// <summary>
 /// blah blah
 /// </summary>
 /// <returns>This function returns a float.</returns>
 private float a()
 {
     return 0;
 }

Now I've added Vector3 b as a parameter like so:

 /// <summary>
 /// blah blah
 /// </summary>
 /// <returns>This function returns a float.</returns>
 private float a(Vector3 b)
 {
     return 0;
 }

Ideally I'm looking for the most efficient way to wind up with the following (note the addition of the "param name" tags) instead of temporarily removing the entire block and generating a new one by typing in the triple slash again.

 /// <summary>
 /// blah blah
 /// </summary>
 /// <returns>This function returns a float.</returns>
 /// <param name="b">The intended direction of motion.</param>
 private float a(Vector3 b)
 {
     return 0;
 }