Since this is a repeat question in my office, I thought I would share the solution with you.  Here are two possible scenarios:
1.  Draw a polyline with an elevation of 0.00 in location "A".  Highlight the polyline and change the elevation to 147.00 and the polyline moves to location "B".
2.  Draw a line at any elevation and location "C".  Highlight the line and change the elevation of one endpoint to a different elevation and the line moves to location "D".
You might even find that if you try to execute a move command on either the polyline or the line from Step 1 or Step 2, they won't appear to move because the elevation doesn't change.
Do you know what the problem is?
The view has been changed to something other than "
Top".
To correct the situation, just type 
-view at the command prompt and then 
top to reset the view.  You can also find the solution in the dropdown menus at 
View-3D Views-Top.