Depends on you. The 1st approach is you could call 1 or you can call on them progressively, adapting if there is/are apparent progress or changes. With “progressively” take for example, you asked Dantalion to make her open towards communicating with me, she contacted you or she replied to your message, yet she doesn’t feel the same love she felt before to you, you should then call another spirit (Duke Sallos, Godesses Aphrodite, Venus, Isis, Archangel Chamuel) or Grand Duke Dantalion again to elicit love to your target (since Dantalion also works with love as well). That’s only an example. You should assess the situation first. Put yourself into her situation at the moment. Examine the situation thoughtfully and choose the demons that are most appropriate for the situation.
The 2nd is layering.
Calling each demon/spirit with different intent. Same advise, examine the situation carefully and choose the demons that are most appropriate for the current situation. Then have them work at the same time. Like take for example, you asked Agares to make her come back to you, to make it possible you asked Dantalion to send positive thoughts of you being together, asked Sitri to make her feel lustful towards me, asked Sallos to rekindle love for me and etc. Here’s an example:
Depends on you which one would you use, but if you would ask me the 1st approach is what most people would suggest. Know that neither approach wont make the end results come fast, you still have to consider that the target could be fighting it but in the end they will succumb to it and you will have the result you wanted even if you have already forgotten about doing a ritual or spirit work, you still have to give them the end of the bargain though (offerings you promised). Priorities are usually the reason. In my case, I know my lover is still pre-occupied with work at the moment since her family is pressuring her and she dont want to be distracted, hence, I know it’ll be slow. On the other hand I know that the spirits are working with my petition behind the scenes because my lover (dont want to call her ex lover 
) is constantly asking my friends and my relatives about me, and she’s constantly stalking me through social media. I know and believe my results will come, I respect her, so I’m not rushing it.
I’m not buying the AV as sign, this one though could be a sign. Especially if the name of your lover is not that common in your place.