In Evony you may want to send resources or troop reinforcements to your allies.
To transport resource to other allies, go to map mode, type the city coordinates where you want to send the transport. Click on the city, then click transport. Select the amount of workers or transporters who will carry the resource. Workers and transporters can carry a lot of resources so are generally used over other types of troops for transporting resources. However, when you want to send resources very quickly you should use scouts. In either case, select the type and amount of resources that you want to send, click Ok.
Reinforcement is when your allies are attacked and you want to send your troops to help him defend his city.
Sending reinforcements is the same as above, but the city where you are going to send reinforcement must have an Embassy. The higher the level the embassy is, the more group of allied troops can be garrisoned there (this does not effect the army size). So, if the city has a level 3 embassy then it can receive and harbour troops from 3 different allies.
The key difference between transporting and reinforcing is that when you transport your troops come back to your town automatically, whereas when you reinforce the troops remain in the destination town until you call them back. The reinforced troops will defend the allies city but they can not be sent to attack another city by the ally. To recall the reinforced troops you have to open "reports" -> "army movements" tab and select the troop to recall. Your ally, to whom sent the reinforcements, can also send them back from their embassy.
Relief Stations greatly minimizes the amount of time required to transport and reinforcements between different cities of your own and ally cities. So if you have cities great distance apart then a high level relief station is a must have. Relief Stations reduce the transport time by 5 percent for each level of upgrade.
This is essential for receiving troop reinforcements. If you don't have an embassy in your city then other ally members cannot reinforce your city. So it is good practice to have an embassy in each of your city and at least up to level 5. The higher the level the embassy is, the more group of allied troops can be garrisoned there (this does not effect the army size). And remember, you must tick the checkbox "Allows troops of the allied members to garrison your current city".
Reinforced troops only take part in defense, they cannot be sent to attack anything else.