Sometimes, it may be up to the escort to contact the client directly to make arrangements for the location and time of an appointment.
Working as an outcall escort is not an offence, and neither is working as a prostitute in private.
It is, however, a criminal offence to pay for services of a prostitute who is controlled for gain if any third party uses force, threat (whether or not relating to violence) or any other form of coercion.
Prostitution in India is legal, In 2010, Mexico Legislators added a law similar to that of the UK called the Anti Trafficking in Persons Act (rough translation) which makes it a crime to offer the sexual services of another person against their will.
The law is still broadly interpreted and has many websites who offered the services of escorts running for cover and even newspapers like El Universal stopped taking classified ads for escorts or "executive massages" because of the law which also goes after anyone promoting the trafficking of persons.
Escort agencies are companies that provide escorts for clients, usually for sexual services.
The agency typically arranges a meeting between one of its escorts and the client at the customer's house or hotel room (outcall), or at the escort's residence (incall).
This fact in turn is well-known to police and the political powers, who, where prostitution is illegal, usually prefer to act against more visible and problematic street prostitution.
This has been criticized as hypocrisy, especially where governments license and tax the escort agencies.
The arm's length relationship between the escort and the escort agency is designed to protect the escort agency (to some degree) from prosecution for breaking laws against prostitution.