Convoke (CR 702.51) allows you to tap creatures as you cast a spell with convoke. Each tapped creature pays for either one generic mana or one mana of any color that creature is. This means a colored mana symbol in the spell's total cost can absolutely be paid by tapping a creature of the matching color.
When you cast a spell with convoke, you first announce the spell and determine its total cost (CR 601.2f). Then, as part of payment, you may tap any number of untapped creatures you control. Each creature reduces the cost by one generic mana or by one mana of a color that creature shares (CR 702.51b). You are not limited to paying only the generic portion.
It is worth noting that convoke does not change the mana cost printed on the card — it is simply an alternative way to pay parts of that cost. Split costs, additional costs, and the like all still apply normally; convoke just provides extra 'payment tokens' in the form of tapped creatures.
Example: You cast Chord of Calling with a cost of {X}{G}{G}{G}. You tap three green creatures to pay for all three {G} symbols, then pay the remaining {X} in mana as normal. The three green creatures satisfied the colored mana requirement entirely through convoke.
One edge case: a multicolored creature can only pay for one mana when tapped via convoke, but you choose which of its colors to apply (CR 702.51b). It does not pay for multiple symbols at once just because it has multiple colors.
Unofficial fan resource — not affiliated with or endorsed by Wizards of the Coast. Answers are AI-generated estimates grounded in the Comprehensive Rules and are not a substitute for an official judge. Verify anything match-critical.