Transfer suggestions
The software can suggest you some moves that are possible and may help you.
The following picture shows that software noticed that you do not need to substitute the 2nd lesson. Instead of assigning new teacher, you can move the lesson from 6th period to 2nd because 6th lesson's teacher has free time:
You can ignore this suggestion and assign any other teacher to substitute the 2nd lesson.
If you decide to accept this suggestion, simply click on the small arrow on the 5th period and select "Suggested moves":
A following dialog appears. As you can see the software suggests to cancel 2nd lesson and move 5th to 2nd. 
Press ok to accept this suggestion. Then on the main screen you can see the result:
Notes:
- the "moved" lines have different color
See also:
Manually moving/changing the lesson
 
                 Slovenčina
								Slovenčina							 Deutsch
								Deutsch							 España
								España							 Francais
								Francais							 Polish
								Polish							 Russian
								Russian							 Čeština
								Čeština							 Greek
								Greek							 Lithuania
								Lithuania							 Romanian
								Romanian							 Arabic
								Arabic							 Português
								Português							 Indonesian
								Indonesian							 Croatian
								Croatian							 Serbia
								Serbia							 Farsi
								Farsi							 Hebrew
								Hebrew							 Mongolian
								Mongolian							 Bulgarian
								Bulgarian							 Georgia
								Georgia							 Azerbaijani
								Azerbaijani							 Thai
								Thai							 Turkish
								Turkish							 Magyar
								Magyar