--- a/lisp/window.el
+++ b/lisp/window.el
@@ -6887,10 +6887,13 @@ WARNING: This is NOT the way to work on another buffer temporarily
 within a Lisp program!  Use `set-buffer' instead.  That avoids
 messing with the window-buffer correspondences.

-If the selected window cannot display the specified
-buffer (e.g. if it is a minibuffer window or strongly dedicated
-to another buffer), call `pop-to-buffer' to select the buffer in
-another window.
+If the selected window cannot display the specified buffer
+because it is a minibuffer window or strongly dedicated to
+another buffer, call `pop-to-buffer' to select the buffer in
+another window.  But if the optional argument FORCE-SAME-WINDOW
+is non-nil and the selected window is strongly dedicated to its
+buffer, prompt the user whether to undedicate the selected window
+first.

 If called interactively, read the buffer name using the
 minibuffer.  The variable `confirm-nonexistent-file-or-buffer'
@@ -6906,10 +6909,6 @@ If optional argument NORECORD is non-nil, do not put the buffer
 at the front of the buffer list, and do not make the window
 displaying it the most recently selected one.

-If optional argument FORCE-SAME-WINDOW is non-nil, the buffer
-must be displayed in the selected window; if that is impossible,
-signal an error rather than calling `pop-to-buffer'.
-
 The option `switch-to-buffer-preserve-window-point' can be used
 to make the buffer appear at its last position in the selected
 window.
@@ -6923,13 +6922,14 @@ Return the buffer switched to."
      ;; might signal an error (e.g. if the window is dedicated).
      ((eq buffer (window-buffer)))
      ((window-minibuffer-p)
-      (if force-same-window
-          (user-error "Cannot switch buffers in minibuffer window")
-        (pop-to-buffer buffer norecord)))
-     ((eq (window-dedicated-p) t)
-      (if force-same-window
-          (user-error "Cannot switch buffers in a dedicated window")
-        (pop-to-buffer buffer norecord)))
+      (pop-to-buffer buffer norecord))
+     ((and (eq (window-dedicated-p) t)
+           (or (not force-same-window)
+               (not (y-or-n-p
+                     (format "Window is dedicated to %s; undedicate it"
+                             (window-buffer))))
+               (set-window-dedicated-p nil nil)))
+      (pop-to-buffer buffer norecord))
      (t
       (let* ((entry (assq buffer (window-prev-buffers)))
 	     (displayed (and (eq switch-to-buffer-preserve-window-point