Simplify the following text for a Grade 12 native English-speaking person.
Original: After a two-year military service at a Panzergrenadier battalion in Ellwangen , he left the Bundeswehr as `` Leutnant der Reserve '' ( reserve officer ) .
Simplified: After a two-year military service at a Panzergrenadier battalion in Ellwangen , he left the Bundeswehr as reserve officer .