A wedding planner may be involved in the process practically from the day after the proposal until the last bubble is blown as the bride and groom leave.
A wedding coordinator, on the other hand, may only be in charge of the ceremony itself. However, the possibility may exist that one person may do both jobs, and simply refers to herself as a coordinator.
The wedding coordinator will certainly be in charge of the ceremony. This will include making sure everyone is present for the ceremony and orchestrating the rehearsal. Wedding Planning – Miriam Avery offers a complete wedding planning and design package to a limited number of couples per year.
For this reason, the coordinator should be someone who is friendly but is not a pushover. She should have enough of a "take charge" attitude that no one will even be tempted to try to overrule her.
If you have a friend or relative who can act as a wedding coordinator without the risk of her being overridden, or (even worse) her taking over completely, making it "her performance" with you and your groom, as well as members of the wedding party simply being the players, then, by all means, ask that person. It might be best, however, to have someone whom you know only slightly or even whom you don't know at all to do the honors.
The wedding coordinator will be responsible for lining up the wedding party and sending them in at the appropriate times. If there are small children who may "balk" at going up the aisle, she should be able to handle them, including knowing when to give up and allow the wedding to proceed.
A good wedding coordinator should consult with the bride and groom beforehand to see if there are certain requests they have or if there is something that needs special attention, such as an elderly family member being given ample time to get down the aisle, as well as familiarize herself with the music that will be used to cue the wedding party members.