What it means

1. verb make a phone call
   “call in to a radio station”
2. verb summon to a particular activity or employment
   “Experts were called in”
3. verb summon to enter
   “The nurse called in the next patient”
4. verb take a player out of a game in order to exchange for another player
5. verb cause to be returned
   “recall the defective auto tires”
6. verb demand payment of (a loan)
   “Call a loan”
7. verb pay a brief visit
   “The mayor likes to call on some of the prominent citizens”